subject:(Magnetic fields)

Columbia University

1. Chen, Shaowen. Transport Measurements of Correlated States in Graphene Flat Bands.

Degree: 2020, Columbia University

URL: https://doi.org/10.7916/d8-7bcb-2d32

► In electronic flat bands the electron kinetic energy is quenched and dominated by interaction and correlated states can emerge. These many-body collective modes are not… (more)

▼ In electronic flat bands the electron kinetic energy is quenched and dominated by interaction and correlated states can emerge. These many-body collective modes are not only interesting enigmas to solve, but may also lead to real-life applications. This thesis studies correlated states in graphene, a tunable system that can be programmed by ex- ternal parameters such as electric field. Two types of graphene flat bands are examined. One, highly degenerate and discreet Landau levels created by external magnetic field. Two, moirè flat bands created by relative crystalline twist between graphene layers. Correlated states are studied with transport measurements. The results were measured in dual-gated graphite/Boron nitride encapsulated graphene heterostructures with very low disorder. The high quality of the heterostructure is showcased by ballistic electron optics including nega- tive refraction across a gate-defined pn junction. In the first type of flat band — a partially filled Landau level — the competition of electrons solid states and fractional quantum Hall liquid manifests as reentrant quantum Hall effect, with a valley and spin hierarchy unique to graphene. Alternatively, in the flat bands arising from moiré superlattices, we explore two tuning knobs of correlated states. In twisted bilayer graphene, the band width are tuned by changing interlayer hybridization via pressure. The resulting superconducting and correlated insulator states can be restored outside of a narrow range of twist angles near 1.1 degrees. New fermi surfaces also form at commensurate fillings of the flat band with reduced degeneracy. In twisted monolayer-bilayer graphene, we find extraordinary level of control and tunability because of the low symmetry. With perpendicular electric field, the system can alternate among correlated metallic and insulating states, as well as topological magnetic states. The magnetization direction can be switched purely with electrostatic doping at zero magnetic field.

Subjects/Keywords: Physics; Graphene; Electrons; Electromagnetic fields; Magnetic fields

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APA (6^th Edition):

Chen, S. (2020). Transport Measurements of Correlated States in Graphene Flat Bands. (Doctoral Dissertation). Columbia University. Retrieved from https://doi.org/10.7916/d8-7bcb-2d32

Chicago Manual of Style (16^th Edition):

Chen, Shaowen. “Transport Measurements of Correlated States in Graphene Flat Bands.” 2020. Doctoral Dissertation, Columbia University. Accessed February 27, 2021. https://doi.org/10.7916/d8-7bcb-2d32.

MLA Handbook (7^th Edition):

Chen, Shaowen. “Transport Measurements of Correlated States in Graphene Flat Bands.” 2020. Web. 27 Feb 2021.

Vancouver:

Chen S. Transport Measurements of Correlated States in Graphene Flat Bands. [Internet] [Doctoral dissertation]. Columbia University; 2020. [cited 2021 Feb 27]. Available from: https://doi.org/10.7916/d8-7bcb-2d32.

Council of Science Editors:

Chen S. Transport Measurements of Correlated States in Graphene Flat Bands. [Doctoral Dissertation]. Columbia University; 2020. Available from: https://doi.org/10.7916/d8-7bcb-2d32

Oregon State University

2. Skorpen, Allan Jerome. Magnetic profiles across the Aleutian Trench and ridge.

Degree: MS, Oceanography, 1967, Oregon State University

URL: http://hdl.handle.net/1957/28141

► During the North Pacific cruise of the R/V Yaquina in 1966, total magnetic field intensity was measured in the Andreanof group of the Aleutian Islands.… (more)

Subjects/Keywords: Magnetic fields

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APA (6^th Edition):

Skorpen, A. J. (1967). Magnetic profiles across the Aleutian Trench and ridge. (Masters Thesis). Oregon State University. Retrieved from http://hdl.handle.net/1957/28141

Chicago Manual of Style (16^th Edition):

Skorpen, Allan Jerome. “Magnetic profiles across the Aleutian Trench and ridge.” 1967. Masters Thesis, Oregon State University. Accessed February 27, 2021. http://hdl.handle.net/1957/28141.

MLA Handbook (7^th Edition):

Skorpen, Allan Jerome. “Magnetic profiles across the Aleutian Trench and ridge.” 1967. Web. 27 Feb 2021.

Vancouver:

Skorpen AJ. Magnetic profiles across the Aleutian Trench and ridge. [Internet] [Masters thesis]. Oregon State University; 1967. [cited 2021 Feb 27]. Available from: http://hdl.handle.net/1957/28141.

Council of Science Editors:

Skorpen AJ. Magnetic profiles across the Aleutian Trench and ridge. [Masters Thesis]. Oregon State University; 1967. Available from: http://hdl.handle.net/1957/28141

Oregon State University

3. Emilia, David Arthur. Numerical methods in the direct interpretation of marine magnetic anomalies.

Degree: PhD, Oceanography, 1968, Oregon State University

URL: http://hdl.handle.net/1957/28266

Subjects/Keywords: Magnetic fields

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APA (6^th Edition):

Emilia, D. A. (1968). Numerical methods in the direct interpretation of marine magnetic anomalies. (Doctoral Dissertation). Oregon State University. Retrieved from http://hdl.handle.net/1957/28266

Chicago Manual of Style (16^th Edition):

Emilia, David Arthur. “Numerical methods in the direct interpretation of marine magnetic anomalies.” 1968. Doctoral Dissertation, Oregon State University. Accessed February 27, 2021. http://hdl.handle.net/1957/28266.

MLA Handbook (7^th Edition):

Emilia, David Arthur. “Numerical methods in the direct interpretation of marine magnetic anomalies.” 1968. Web. 27 Feb 2021.

Vancouver:

Emilia DA. Numerical methods in the direct interpretation of marine magnetic anomalies. [Internet] [Doctoral dissertation]. Oregon State University; 1968. [cited 2021 Feb 27]. Available from: http://hdl.handle.net/1957/28266.

Council of Science Editors:

Emilia DA. Numerical methods in the direct interpretation of marine magnetic anomalies. [Doctoral Dissertation]. Oregon State University; 1968. Available from: http://hdl.handle.net/1957/28266

Oregon State University

4. Ranawake, Udaya A. Preliminary studies on a magnetic elevator for solids (MES).

Degree: MS, Electrical and Computer Engineering, 1987, Oregon State University

URL: http://hdl.handle.net/1957/39897

► The thesis describes the preliminary studies on a laboratory model of a magnetic elevator intended as part of a system for circulating magnetic materials in… (more)

Subjects/Keywords: Magnetic fields

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APA (6^th Edition):

Ranawake, U. A. (1987). Preliminary studies on a magnetic elevator for solids (MES). (Masters Thesis). Oregon State University. Retrieved from http://hdl.handle.net/1957/39897

Chicago Manual of Style (16^th Edition):

Ranawake, Udaya A. “Preliminary studies on a magnetic elevator for solids (MES).” 1987. Masters Thesis, Oregon State University. Accessed February 27, 2021. http://hdl.handle.net/1957/39897.

MLA Handbook (7^th Edition):

Ranawake, Udaya A. “Preliminary studies on a magnetic elevator for solids (MES).” 1987. Web. 27 Feb 2021.

Vancouver:

Ranawake UA. Preliminary studies on a magnetic elevator for solids (MES). [Internet] [Masters thesis]. Oregon State University; 1987. [cited 2021 Feb 27]. Available from: http://hdl.handle.net/1957/39897.

Council of Science Editors:

Ranawake UA. Preliminary studies on a magnetic elevator for solids (MES). [Masters Thesis]. Oregon State University; 1987. Available from: http://hdl.handle.net/1957/39897

Addis Ababa University

5. Feyisso, Sado. NON-DIPOLAR COMPONENTS OF PULSAR MAGNETIC FIELDS .

Degree: 2012, Addis Ababa University

URL: http://etd.aau.edu.et/dspace/handle/123456789/1230

► The recent observations indicate that the presence of non-dipolar pulsars magnetic fields. Post-Newtonian approximation(PN) used in solving Einstein’s field equation in general relativity was made… (more)

Subjects/Keywords: NON-DIPOLAR; PULSAR; MAGNETIC FIELDS

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APA (6^th Edition):

Feyisso, S. (2012). NON-DIPOLAR COMPONENTS OF PULSAR MAGNETIC FIELDS . (Thesis). Addis Ababa University. Retrieved from http://etd.aau.edu.et/dspace/handle/123456789/1230

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Feyisso, Sado. “NON-DIPOLAR COMPONENTS OF PULSAR MAGNETIC FIELDS .” 2012. Thesis, Addis Ababa University. Accessed February 27, 2021. http://etd.aau.edu.et/dspace/handle/123456789/1230.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Feyisso, Sado. “NON-DIPOLAR COMPONENTS OF PULSAR MAGNETIC FIELDS .” 2012. Web. 27 Feb 2021.

Vancouver:

Feyisso S. NON-DIPOLAR COMPONENTS OF PULSAR MAGNETIC FIELDS . [Internet] [Thesis]. Addis Ababa University; 2012. [cited 2021 Feb 27]. Available from: http://etd.aau.edu.et/dspace/handle/123456789/1230.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Feyisso S. NON-DIPOLAR COMPONENTS OF PULSAR MAGNETIC FIELDS . [Thesis]. Addis Ababa University; 2012. Available from: http://etd.aau.edu.et/dspace/handle/123456789/1230

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of North Texas

6. Pathapati Subbu, Kalyan Sasidhar. Indoor Localization Using Magnetic Fields.

Degree: 2011, University of North Texas

URL: https://digital.library.unt.edu/ark:/67531/metadc103371/

► Indoor localization consists of locating oneself inside new buildings. GPS does not work indoors due to multipath reflection and signal blockage. WiFi based systems assume… (more)

▼ Indoor localization consists of locating oneself inside new buildings. GPS does not work indoors due to multipath reflection and signal blockage. WiFi based systems assume ubiquitous availability and infrastructure based systems require expensive installations, hence making indoor localization an open problem. This dissertation consists of solving the problem of indoor localization by thoroughly exploiting the indoor ambient magnetic fields comprising mainly of disturbances termed as anomalies in the Earth’s magnetic field caused by pillars, doors and elevators in hallways which are ferromagnetic in nature. By observing uniqueness in magnetic signatures collected from different campus buildings, the work presents the identification of landmarks and guideposts from these signatures and further develops magnetic maps of buildings - all of which can be used to locate and navigate people indoors. To understand the reason behind these anomalies, first a comparison between the measured and model generated Earth’s magnetic field is made, verifying the presence of a constant field without any disturbances. Then by modeling the magnetic field behavior of different pillars such as steel reinforced concrete, solid steel, and other structures like doors and elevators, the interaction of the Earth’s field with the ferromagnetic fields is described thereby explaining the causes of the uniqueness in the signatures that comprise these disturbances. Next, by employing the dynamic time warping algorithm to account for time differences in signatures obtained from users walking at different speeds, an indoor localization application capable of classifying locations using the magnetic signatures is developed solely on the smart phone. The application required users to walk short distances of 3-6 m anywhere in hallway to be located with accuracies of 80-99%. The classification framework was further validated with over 90% accuracies using model generated magnetic signatures representing hallways with different kinds of pillars, doors and elevators. All in all, this dissertation contributes the following: 1) provides a framework for understanding the presence of ambient magnetic fields indoors and utilizing them to solve the indoor localization problem; 2) develops an application that is independent of the user and the smart phones and 3) requires no other infrastructure since it is deployed on a device that encapsulates the sensing, computing and inferring functionalities, thereby making it a novel contribution to the mobile and pervasive computing domain. Advisors/Committee Members: Dantu, Ram, Sweany, Philip H., Tarau, Paul, Wang, Zuoming.

Subjects/Keywords: Localization; magnetic fields; smartphones

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APA (6^th Edition):

Pathapati Subbu, K. S. (2011). Indoor Localization Using Magnetic Fields. (Thesis). University of North Texas. Retrieved from https://digital.library.unt.edu/ark:/67531/metadc103371/

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Pathapati Subbu, Kalyan Sasidhar. “Indoor Localization Using Magnetic Fields.” 2011. Thesis, University of North Texas. Accessed February 27, 2021. https://digital.library.unt.edu/ark:/67531/metadc103371/.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Pathapati Subbu, Kalyan Sasidhar. “Indoor Localization Using Magnetic Fields.” 2011. Web. 27 Feb 2021.

Vancouver:

Pathapati Subbu KS. Indoor Localization Using Magnetic Fields. [Internet] [Thesis]. University of North Texas; 2011. [cited 2021 Feb 27]. Available from: https://digital.library.unt.edu/ark:/67531/metadc103371/.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Pathapati Subbu KS. Indoor Localization Using Magnetic Fields. [Thesis]. University of North Texas; 2011. Available from: https://digital.library.unt.edu/ark:/67531/metadc103371/

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Boston University

7. Hoq, Sadia. Magnetic fields in the Perseus spiral arm and in infrared dark clouds.

Degree: PhD, Astronomy, 2017, Boston University

URL: http://hdl.handle.net/2144/20717

► The magnetic (B) field is ubiquitous throughout the Milky Way. Several fundamental questions about the B-field in the cool, star-forming interstellar medium (ISM) remain unanswered.… (more)

▼ The magnetic (B) field is ubiquitous throughout the Milky Way. Several fundamental questions about the B-field in the cool, star-forming interstellar medium (ISM) remain unanswered. In this dissertation, near-infrared (NIR) polarimetric observations are used to study the large-scale Galactic B-field in the cool ISM in a spiral arm and to determine the role of B-fields in the formation of Infrared Dark Clouds (IRDCs). NIR polarimetry of 31 star clusters, located in and around the Perseus spiral arm, were obtained to determine the orientation of the plane-of-sky B-field in the outer Galaxy, and whether the presence of a spiral arm influenced B-field properties. Cluster distances, which provide upper limits to the B-field probed by observations, were estimated by developing a maximum likelihood method to fit theoretical stellar isochrones to stars in cluster color-magnitude diagrams (CMDs). Using the distance estimates, the cluster locations relative to the Perseus arm were found. The cluster polarization percentages and orientations were compared between clusters foreground to the arm and clusters inside or behind the arm. The cluster polarization orientations are predominantly parallel to the Galactic plane. Clusters inside and behind the arm have larger polarization percentages, likely a result of more polarizing material along the line of sight. The cluster polarization data were also compared to optical, inner Galaxy NIR, and Planck submm polarimetry data, and showed agreement with all three data sets. The polarimetric properties of one IRDC, G28.23, were determined using deep NIR observations. The polarization orientations relative to the cloud major axis were found to change directions with distance from the cloud axis. The B-field strength was estimated to be 10 to 100uG. Despite these large inferred B-field strengths, the B-field was found not to be the dominant force in the formation of the IRDC, though the B-field morphology was influenced by the cloud. Using NIR observations, the B-field of 27 IRDCs were studied. The relative polarization orientations with respect to the cloud major axes were found. No preferential relative orientation was found, implying that the B-field did not greatly influence the formation of this sample of IRDCs.

Subjects/Keywords: Astronomy; Magnetic fields; Polarization

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APA (6^th Edition):

Hoq, S. (2017). Magnetic fields in the Perseus spiral arm and in infrared dark clouds. (Doctoral Dissertation). Boston University. Retrieved from http://hdl.handle.net/2144/20717

Chicago Manual of Style (16^th Edition):

Hoq, Sadia. “Magnetic fields in the Perseus spiral arm and in infrared dark clouds.” 2017. Doctoral Dissertation, Boston University. Accessed February 27, 2021. http://hdl.handle.net/2144/20717.

MLA Handbook (7^th Edition):

Hoq, Sadia. “Magnetic fields in the Perseus spiral arm and in infrared dark clouds.” 2017. Web. 27 Feb 2021.

Vancouver:

Hoq S. Magnetic fields in the Perseus spiral arm and in infrared dark clouds. [Internet] [Doctoral dissertation]. Boston University; 2017. [cited 2021 Feb 27]. Available from: http://hdl.handle.net/2144/20717.

Council of Science Editors:

Hoq S. Magnetic fields in the Perseus spiral arm and in infrared dark clouds. [Doctoral Dissertation]. Boston University; 2017. Available from: http://hdl.handle.net/2144/20717

University of St. Andrews

8. Fuentes Fernández, Jorge. MHD evolution of magnetic null points to static equilibria .

Degree: 2011, University of St. Andrews

URL: http://hdl.handle.net/10023/1897

► In magnetised plasmas, magnetic reconnection is the process of magnetic field merging and recombination through which considerable amounts of magnetic energy may be converted into… (more)

▼ In magnetised plasmas, magnetic reconnection is the process of magnetic field merging and recombination through which considerable amounts of magnetic energy may be converted into other forms of energy. Reconnection is a key mechanism for solar flares and coronal mass ejections in the solar atmosphere, it is believed to be an important source of heating of the solar corona, and it plays a major role in the acceleration of particles in the Earth's magnetotail. For reconnection to occur, the magnetic field must, in localised regions, be able to diffuse through the plasma. Ideal locations for diffusion to occur are electric current layers formed from rapidly changing magnetic fields in short space scales. In this thesis we consider the formation and nature of these current layers in magnetised plasmas. The study of current sheets and current layers in two, and more recently, three dimensions, has been a key field of research in the last decades. However, many of these studies do not take plasma pressure effects into consideration, and rather they consider models of current sheets where the magnetic forces sum to zero. More recently, others have started to consider models in which the plasma beta is non-zero, but they simply focus on the actual equilibrium state involving a current layer and do not consider how such an equilibrium may be achieved physically. In particular, they do not allow energy conversion between magnetic and internal energy of the plasma on their way to approaching the final equilibrium. In this thesis, we aim to describe the formation of equilibrium states involving current layers at both two and three dimensional magnetic null points, which are specific locations where the magnetic field vanishes. The different equilibria are obtained through the non-resistive dynamical evolution of perturbed hydromagnetic systems. The dynamic evolution relaxes via viscous damping, resulting in viscous heating. We have run a series of numerical experiments using LARE, a Lagrangian-remap code, that solves the full magnetohydrodynamic (MHD) equations with user controlled viscosity and resistivity. To allow strong current accumulations to be created in a static equilibrium, we set the resistivity to be zero and hence simply reach our equilibria by solving the ideal MHD equations. We first consider the relaxation of simple homogeneous straight magnetic fields embedded in a plasma, and determine the role of the coupling between magnetic and plasma forces, both analytically and numerically. Then, we study the formation of current accumulations at 2D magnetic X-points and at 3D magnetic nulls with spine-aligned and fan-aligned current. At both 2D X-points and 3D nulls with fan-aligned current, the current density becomes singular at the location of the null. It is impossible to be precisely achieve an exact singularity, and instead, we find a gradual continuous increase of the peak current over time, and small, highly localised forces acting to form the singularity. In the 2D case, we give a qualitative… Advisors/Committee Members: Parnell, Clare Elizabeth (advisor).

Subjects/Keywords: Sun; Magnetic fields; Reconnection

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APA (6^th Edition):

Fuentes Fernández, J. (2011). MHD evolution of magnetic null points to static equilibria . (Thesis). University of St. Andrews. Retrieved from http://hdl.handle.net/10023/1897

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Fuentes Fernández, Jorge. “MHD evolution of magnetic null points to static equilibria .” 2011. Thesis, University of St. Andrews. Accessed February 27, 2021. http://hdl.handle.net/10023/1897.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Fuentes Fernández, Jorge. “MHD evolution of magnetic null points to static equilibria .” 2011. Web. 27 Feb 2021.

Vancouver:

Fuentes Fernández J. MHD evolution of magnetic null points to static equilibria . [Internet] [Thesis]. University of St. Andrews; 2011. [cited 2021 Feb 27]. Available from: http://hdl.handle.net/10023/1897.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Fuentes Fernández J. MHD evolution of magnetic null points to static equilibria . [Thesis]. University of St. Andrews; 2011. Available from: http://hdl.handle.net/10023/1897

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Montana State University

9. Kobelski, Adam Robert. Empirical studies on the initiation of impulsive heating in coronal loops.

Degree: PhD, College of Letters & Science, 2014, Montana State University

URL: https://scholarworks.montana.edu/xmlui/handle/1/8697

► The heating of the solar corona is an important topic both for scientists and modern society. One of the most fundamental of structures in the… (more)

Subjects/Keywords: Solar magnetic fields.; Solar flares.

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APA (6^th Edition):

Kobelski, A. R. (2014). Empirical studies on the initiation of impulsive heating in coronal loops. (Doctoral Dissertation). Montana State University. Retrieved from https://scholarworks.montana.edu/xmlui/handle/1/8697

Chicago Manual of Style (16^th Edition):

Kobelski, Adam Robert. “Empirical studies on the initiation of impulsive heating in coronal loops.” 2014. Doctoral Dissertation, Montana State University. Accessed February 27, 2021. https://scholarworks.montana.edu/xmlui/handle/1/8697.

MLA Handbook (7^th Edition):

Kobelski, Adam Robert. “Empirical studies on the initiation of impulsive heating in coronal loops.” 2014. Web. 27 Feb 2021.

Vancouver:

Kobelski AR. Empirical studies on the initiation of impulsive heating in coronal loops. [Internet] [Doctoral dissertation]. Montana State University; 2014. [cited 2021 Feb 27]. Available from: https://scholarworks.montana.edu/xmlui/handle/1/8697.

Council of Science Editors:

Kobelski AR. Empirical studies on the initiation of impulsive heating in coronal loops. [Doctoral Dissertation]. Montana State University; 2014. Available from: https://scholarworks.montana.edu/xmlui/handle/1/8697

10. Flaux, Pierrick. Measurement of the neutron electric dipole moment at the Paul Scherrer Institute : production of magnetic fields : Mesure du moment dipolaire électrique du neutron à l'Institut Paul Scherrer : production de champs magnétiques pour l'expérience n2EDM.

Degree: Docteur es, Physique, 2019, Normandie

URL: http://www.theses.fr/2019NORMC222

►

Le travail réalisé au cours de cette thèse concerne le développement du système de bobines de l'expérience n2EDM à l'Institut Paul Sherrer (PSI). Le but… (more)

▼

Le travail réalisé au cours de cette thèse concerne le développement du système de bobines de l'expérience n2EDM à l'Institut Paul Sherrer (PSI). Le but de cette expérience est de mettre en évidence de nouvelles sources de violation CP à travers la mesure du moment dipolaire électrique du neutron. L'actuelle limite supérieure sur la mesure de nEDM, 2.9 x 10⁻²⁶ e.cm (90% C.L.) à été obtenue par la collaboration RAL-Sussex-ILL en 2006.L'expérience n2EDM vise à améliorer d'un ordre de grandeur la sensibilité statistique en gardant sous contrôle les effets systématiques. Cela requiert la production d'un champ magnétique très uniforme. Les non-uniformités de ce dernier sont en effet responsable de la dépolarisation des neutrons et impliqués dans plusieurs effets systématiques.Dans le premier chapitre, les motivations physiques sont discutées. Le second chapitre décrit le principe de mesure de l'expérience n2EDM, ainsi que l'importance de l'uniformité du champ magnétique. Le chapitre s'achève par une présentation globale du dispositif expérimental. Le troisième chapitre présente le logiciel COMSOL et discute du design et des performances de la bobine B₀, en charge de la production du champ magnétique principal. Dans le quatrième chapitre, le système de bobines correctrices chargées de corriger les non-uniformités du champ magnétique et celles devant produire des gradients spécifiques sont présentées. Finalement, le cinquième et dernier chapitre présente l'étude des dipôles magnétiques localisés et de leur influence sur l'expérience.

This work presents the design of the coils system developed for the n2EDM experiment at the Paul Sherrer Institute (PSI). The goal of this experiment is to reveal new sources of CP violation through the measurement of the neutron electric dipole moment. The current upper limit of the nEDM measurement, 2.9 x 10⁻²⁶ e.cm (90% C.L.) was achieved by the RAL-Sussex-ILL collaboration in 2006. The n2EDM experiment aims at improving by one order of magnitude the statistical sensitivity while keeping under control the systematics effects. It requires to produce a very uniform field, its non-uniformities being responsible of the neutron's depolarization and of severals systematic effects.In the first chapter, the theoretical motivation are discussed.The second chapter describes the measurement principle of the n2EDM experiment, as well as the importance of the magnetic field uniformity. This chapter ends by an overview of the apparatus. The third chapter introduces the COMSOL software and discuss the design and the performances of the B₀ coil, in charge of the production of the main magnetic field. In the fourth chapter, the correcting coils used to suppress the non-uniformities of the magnetic field and the ones which produce specific gradients are presented. Finally, the fifth and last chapter talks about the study of localised magnetic dipoles and their influence on the experiment.

Advisors/Committee Members: Ban, Gilles (thesis director).

Subjects/Keywords: EDM; UCN; Magnetic fields; COMSOL

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APA (6^th Edition):

Flaux, P. (2019). Measurement of the neutron electric dipole moment at the Paul Scherrer Institute : production of magnetic fields : Mesure du moment dipolaire électrique du neutron à l'Institut Paul Scherrer : production de champs magnétiques pour l'expérience n2EDM. (Doctoral Dissertation). Normandie. Retrieved from http://www.theses.fr/2019NORMC222

Chicago Manual of Style (16^th Edition):

Flaux, Pierrick. “Measurement of the neutron electric dipole moment at the Paul Scherrer Institute : production of magnetic fields : Mesure du moment dipolaire électrique du neutron à l'Institut Paul Scherrer : production de champs magnétiques pour l'expérience n2EDM.” 2019. Doctoral Dissertation, Normandie. Accessed February 27, 2021. http://www.theses.fr/2019NORMC222.

MLA Handbook (7^th Edition):

Flaux, Pierrick. “Measurement of the neutron electric dipole moment at the Paul Scherrer Institute : production of magnetic fields : Mesure du moment dipolaire électrique du neutron à l'Institut Paul Scherrer : production de champs magnétiques pour l'expérience n2EDM.” 2019. Web. 27 Feb 2021.

Vancouver:

Flaux P. Measurement of the neutron electric dipole moment at the Paul Scherrer Institute : production of magnetic fields : Mesure du moment dipolaire électrique du neutron à l'Institut Paul Scherrer : production de champs magnétiques pour l'expérience n2EDM. [Internet] [Doctoral dissertation]. Normandie; 2019. [cited 2021 Feb 27]. Available from: http://www.theses.fr/2019NORMC222.

Council of Science Editors:

Flaux P. Measurement of the neutron electric dipole moment at the Paul Scherrer Institute : production of magnetic fields : Mesure du moment dipolaire électrique du neutron à l'Institut Paul Scherrer : production de champs magnétiques pour l'expérience n2EDM. [Doctoral Dissertation]. Normandie; 2019. Available from: http://www.theses.fr/2019NORMC222

University of St. Andrews

11. O'Hara, Jennifer. Numerical simulations of footpoint driven coronal heating .

Degree: 2016, University of St. Andrews

URL: http://hdl.handle.net/10023/8871

► Magnetic field permeates the solar atmosphere and plays a crucial role in the dynamics, energetics and structures observed. In particular, magnetic flux tubes provide the… (more)

Subjects/Keywords: Magnetohydrodynamics; Sun – Corona; Magnetic fields

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APA (6^th Edition):

O'Hara, J. (2016). Numerical simulations of footpoint driven coronal heating . (Thesis). University of St. Andrews. Retrieved from http://hdl.handle.net/10023/8871

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

O'Hara, Jennifer. “Numerical simulations of footpoint driven coronal heating .” 2016. Thesis, University of St. Andrews. Accessed February 27, 2021. http://hdl.handle.net/10023/8871.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

O'Hara, Jennifer. “Numerical simulations of footpoint driven coronal heating .” 2016. Web. 27 Feb 2021.

Vancouver:

O'Hara J. Numerical simulations of footpoint driven coronal heating . [Internet] [Thesis]. University of St. Andrews; 2016. [cited 2021 Feb 27]. Available from: http://hdl.handle.net/10023/8871.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

O'Hara J. Numerical simulations of footpoint driven coronal heating . [Thesis]. University of St. Andrews; 2016. Available from: http://hdl.handle.net/10023/8871

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Hong Kong University of Science and Technology

12. Zhang, Lixia. Magnetic field effect in small molecule organic semiconductors.

Degree: 2016, Hong Kong University of Science and Technology

URL: http://repository.ust.hk/ir/Record/1783.1-82353 ; https://doi.org/10.14711/thesis-b1610619 ; http://repository.ust.hk/ir/bitstream/1783.1-82353/1/th_redirect.html

► The magnetic field effect (MFE) exerted on charge transport and energy transfer processes in fluorescent small molecule organic semiconductors has been investigated in this thesis.… (more)

▼ The magnetic field effect (MFE) exerted on charge transport and energy transfer processes in fluorescent small molecule organic semiconductors has been investigated in this thesis. By varying both internal factors such as device structures and external factors such as bias applied, various MFEs have been observed and identified in conductance, photocurrent, photoluminescence (PL), and electroluminescence (EL) measurements at room temperature. The observed MFEs generally consist of so-called low MFE (< 10 mT) and high MFE (< 10 mT) components and can exhibit either positive or negative field dependence. The low MFE is attributed to magnetic field suppression of electron-hole pairs spin mixing via hyperfine interaction between electron spin and nuclear spin. But the triplet-exciton-polaron interaction (T_XPI) is responsible for the high MFE. The trion model has been used to explain the underlying physical origin for T_XPI mechanism with the hypothesis of the doublet and quartet trions as the intermediate states. The magnetic field suppression of spin mixing between doublet and quartet trions results in the various high magnetic field effects. Polaron trapping and de-trapping processes based on T_X-free polaron interaction and T_X-trapped polaron interaction have been identified in NPB based single layer devices. The different characteristic magnetic fields of T_XPI are determined by zero field splitting of T_X and the different electronic coupling between T_X and free/trapped polarons. The magnetic field suppressed energy transfer based on T_xPI has been observed. The existence of doublet trion has been proved with its life time determined to be ~ 120 ps at room temperature in NPB doped by DCJTB device. The T_XPI based energy transfer plays the decisive role in EL generation in doped OLEDs. The evidence of the electronic coupling between T_x and polaron has been proved by the resonance effect in MFE on EL in DCJTB doped organic light emitting diodes. The positive effect of the T_xPI based energy transfer processes can enhance external quantum efficiency of fluorescent doped organic light emitting diodes.

Subjects/Keywords: Organic semiconductors ; Magnetic properties ; Magnetic fields

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APA (6^th Edition):

Zhang, L. (2016). Magnetic field effect in small molecule organic semiconductors. (Thesis). Hong Kong University of Science and Technology. Retrieved from http://repository.ust.hk/ir/Record/1783.1-82353 ; https://doi.org/10.14711/thesis-b1610619 ; http://repository.ust.hk/ir/bitstream/1783.1-82353/1/th_redirect.html

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Zhang, Lixia. “Magnetic field effect in small molecule organic semiconductors.” 2016. Thesis, Hong Kong University of Science and Technology. Accessed February 27, 2021. http://repository.ust.hk/ir/Record/1783.1-82353 ; https://doi.org/10.14711/thesis-b1610619 ; http://repository.ust.hk/ir/bitstream/1783.1-82353/1/th_redirect.html.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Zhang, Lixia. “Magnetic field effect in small molecule organic semiconductors.” 2016. Web. 27 Feb 2021.

Vancouver:

Zhang L. Magnetic field effect in small molecule organic semiconductors. [Internet] [Thesis]. Hong Kong University of Science and Technology; 2016. [cited 2021 Feb 27]. Available from: http://repository.ust.hk/ir/Record/1783.1-82353 ; https://doi.org/10.14711/thesis-b1610619 ; http://repository.ust.hk/ir/bitstream/1783.1-82353/1/th_redirect.html.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Zhang L. Magnetic field effect in small molecule organic semiconductors. [Thesis]. Hong Kong University of Science and Technology; 2016. Available from: http://repository.ust.hk/ir/Record/1783.1-82353 ; https://doi.org/10.14711/thesis-b1610619 ; http://repository.ust.hk/ir/bitstream/1783.1-82353/1/th_redirect.html

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of North Texas

13. Coker, Zachary. Deleterious Synergistic Effects of Concurrent Magnetic Field and Superparamagnetic (Fe3O4) Nanoparticle Exposures on CHO-K1 Cell Line.

Degree: 2015, University of North Texas

URL: https://digital.library.unt.edu/ark:/67531/metadc799479/

► While many investigations have been performed to establish a better understanding of the effects that magnetic fields and nanoparticles have on cells, the fundamental mechanisms… (more)

Subjects/Keywords: concurrent exposure; magnetic fields; magnetic nanoparticles; SPION; extreme-low frequency; Magnetic fields.; Nanoparticles.; Cell lines.

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APA (6^th Edition):

Coker, Z. (2015). Deleterious Synergistic Effects of Concurrent Magnetic Field and Superparamagnetic (Fe3O4) Nanoparticle Exposures on CHO-K1 Cell Line. (Thesis). University of North Texas. Retrieved from https://digital.library.unt.edu/ark:/67531/metadc799479/

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Coker, Zachary. “Deleterious Synergistic Effects of Concurrent Magnetic Field and Superparamagnetic (Fe3O4) Nanoparticle Exposures on CHO-K1 Cell Line.” 2015. Thesis, University of North Texas. Accessed February 27, 2021. https://digital.library.unt.edu/ark:/67531/metadc799479/.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Coker, Zachary. “Deleterious Synergistic Effects of Concurrent Magnetic Field and Superparamagnetic (Fe3O4) Nanoparticle Exposures on CHO-K1 Cell Line.” 2015. Web. 27 Feb 2021.

Vancouver:

Coker Z. Deleterious Synergistic Effects of Concurrent Magnetic Field and Superparamagnetic (Fe3O4) Nanoparticle Exposures on CHO-K1 Cell Line. [Internet] [Thesis]. University of North Texas; 2015. [cited 2021 Feb 27]. Available from: https://digital.library.unt.edu/ark:/67531/metadc799479/.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Coker Z. Deleterious Synergistic Effects of Concurrent Magnetic Field and Superparamagnetic (Fe3O4) Nanoparticle Exposures on CHO-K1 Cell Line. [Thesis]. University of North Texas; 2015. Available from: https://digital.library.unt.edu/ark:/67531/metadc799479/

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

14. Williams, Benjamin Matthew. The dynamic topology of the solar corona : mapping the Sun’s three dimensional magnetic skeleton .

Degree: 2018, University of St. Andrews

URL: http://hdl.handle.net/10023/14637

► Observations of the surface of the Sun reveal multi-scaled, mixed magnetic features that carpet the entire solar surface. Not surprisingly, the global magnetic fields extrapolated… (more)

▼ Observations of the surface of the Sun reveal multi-scaled, mixed magnetic features that carpet the entire solar surface. Not surprisingly, the global magnetic fields extrapolated from these observations are highly complex. This thesis explores the topology of the Sun’s global coronal magnetic fields. The magnetic skeleton of a magnetic field provides us with a way of examining the magnetic field and quantifying its complexity. Using specialised codes to find the magnetic skeletons which were written during the course of this work, we first examine potential field extrapolations of the global solar coronal magnetic field determined from observed synoptic magnetograms from the Heliospheric Magnetic Imager on the Solar Dynamics Observatory. The resolution of the PFSS models is found to be very important for discovering the true nature of the global magnetic skeleton. By increasing the maximum number of harmonics used in the potential field extrapolations and, therefore, the grid resolution, 60 times more null points may be found in the coronal magnetic field. These high resolution fields also have a large global separator network which connects the coronal magnetic field over large distances and involves between 40 % and 60 % of all the null points in the solar atmosphere. This global separator network exists at both solar minimum and solar maximum and has separators that reach high into the solar atmosphere (> 1R☉) even though they connect null points close to the solar surface. These potential field extrapolations are then compared with magnetohydrostatic (MHS) extrapolations of the coronal magnetic field which also provide us with information about the plasma in the corona. With a small component of electric current density in the direction perpendicular to the radial direction, these MHS fields are found to have a plasma beta and pressure typical of the corona. As this small component of electric current density grows, the heliospheric current sheet is warped significantly and the magnetic field, plasma beta and pressure become unphysical. Torsional spine reconnection is also studied local to a single null point. First using a dynamical relaxation of a spiral null point under non-resistive magnetohydrodynamics (MHD) to a MHS equilibrium is form in which a current layer has built up around the spine lines. Then the reconnection under resistive MHD in this current sheet is studied. The current about the spine lines is dissipated and the magnetic energy is mainly converted into heat directly as the field lines untwist about the spine line. Advisors/Committee Members: Parnell, Clare Elizabeth (advisor).

Subjects/Keywords: Magnetic fields; Magnetic reconnection; Magnetic topology; Sun; Magnetohydrodynamics; Numerical methods; Magnetic null points

10 more images…

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APA (6^th Edition):

Williams, B. M. (2018). The dynamic topology of the solar corona : mapping the Sun’s three dimensional magnetic skeleton . (Thesis). University of St. Andrews. Retrieved from http://hdl.handle.net/10023/14637

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Williams, Benjamin Matthew. “The dynamic topology of the solar corona : mapping the Sun’s three dimensional magnetic skeleton .” 2018. Thesis, University of St. Andrews. Accessed February 27, 2021. http://hdl.handle.net/10023/14637.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Williams, Benjamin Matthew. “The dynamic topology of the solar corona : mapping the Sun’s three dimensional magnetic skeleton .” 2018. Web. 27 Feb 2021.

Vancouver:

Williams BM. The dynamic topology of the solar corona : mapping the Sun’s three dimensional magnetic skeleton . [Internet] [Thesis]. University of St. Andrews; 2018. [cited 2021 Feb 27]. Available from: http://hdl.handle.net/10023/14637.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Williams BM. The dynamic topology of the solar corona : mapping the Sun’s three dimensional magnetic skeleton . [Thesis]. University of St. Andrews; 2018. Available from: http://hdl.handle.net/10023/14637

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of California – Berkeley

15. Slusky, Danna Aharon. Methodological Issues in Exposure Assessment for Studies of Childhood Leukemia.

Degree: Epidemiology, 2010, University of California – Berkeley

URL: http://www.escholarship.org/uc/item/90j4w3jw

► This dissertation examined several methodological aspects of case control studies potentially influencing the association of environmental exposures with the risk of childhood leukemia. These aspects… (more)

▼ This dissertation examined several methodological aspects of case control studies potentially influencing the association of environmental exposures with the risk of childhood leukemia. These aspects included the role of SES and racial distribution on subjects' participation, the role of selection bias on the association between EMF and childhood leukemia, as well as reproducibility of self-reports of household pesticide exposure. The research presented in this dissertation was made possible by the Northern California Childhood Leukemia Study, an ongoing population-based case-control study, which commenced in 1995. Results of meta-analyses suggest that in interview based case-control studies, cases were more likely to be non-White than White with an overall OR of 1.37 (95% CI 1.13, 1.67). In contrast, in the record-based studies cases, compared to controls, were less likely to be non-White than White, with an overall OR of 0.81 (95% CI 0.72,0.91). Results also indicated that SES was inversely associated with childhood leukemia while using interview based study design while positive association was observed while using record based study design. Chapter Four of this dissertation examined the association between childhood leukemia and extremely low frequency of magnetic fields (measured by wire coding) with an emphasis on selection bias. Results indicated that the observed risk estimate depends on the selected control group. The odds ratios (OR) for developing childhood leukemia in the high-current configurations category were 1.43 (95% confidence interval (CI): 0.91, 2.26) compared to the first choice participant controls, while no associations were observed when compared to non-first choice participant controls (OR=1.06, 95% CI: 0.71-1.60) or first choice non-participant controls (OR=1.06, 95% CI: 0.71-1.57). Overall, no association was found between childhood leukemia and EMF as measured by wire configuration codes. Ideal (participating and non-participating) cases assigned to high-current configurations experience a non-significant increased risk of childhood leukemia, when compared to the ideal controls (OR=1.18, 95% CI: 0.85-1.64). Chapter Five assessed the reproducibility of maternal-reported household use of pesticides and potential differential recall between cases and controls. Results indicated that the Kappa statistics ranged from 0.31 to 0.61 (fair to substantial agreement), with 9 out of the 12 tests indicating moderate agreement. The percent positive agreement ranged from 46-80% and the percent negative agreement from 54-95%. Results indicated that the reliability of self-reported exposures for all pesticide categories using the three reliability measures did not differ markedly for cases and controls as confirmed by bootstrap analysis.

Subjects/Keywords: Epidemiology; Childhood Leukemia; Magnetic Fields; Selection Bias

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APA (6^th Edition):

Slusky, D. A. (2010). Methodological Issues in Exposure Assessment for Studies of Childhood Leukemia. (Thesis). University of California – Berkeley. Retrieved from http://www.escholarship.org/uc/item/90j4w3jw

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Slusky, Danna Aharon. “Methodological Issues in Exposure Assessment for Studies of Childhood Leukemia.” 2010. Thesis, University of California – Berkeley. Accessed February 27, 2021. http://www.escholarship.org/uc/item/90j4w3jw.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Slusky, Danna Aharon. “Methodological Issues in Exposure Assessment for Studies of Childhood Leukemia.” 2010. Web. 27 Feb 2021.

Vancouver:

Slusky DA. Methodological Issues in Exposure Assessment for Studies of Childhood Leukemia. [Internet] [Thesis]. University of California – Berkeley; 2010. [cited 2021 Feb 27]. Available from: http://www.escholarship.org/uc/item/90j4w3jw.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Slusky DA. Methodological Issues in Exposure Assessment for Studies of Childhood Leukemia. [Thesis]. University of California – Berkeley; 2010. Available from: http://www.escholarship.org/uc/item/90j4w3jw

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

UCLA

16. Arlen, Timothy. Constraining the Intergalactic Magnetic Field Through its Imprint on Gamma Ray Data from Distant Sources.

Degree: Physics, 2013, UCLA

URL: http://www.escholarship.org/uc/item/0gv406rt

► Gamma ray photons, with energies >TeV propagating cosmological distances will be attenuated by pair production with diffuse extragalactic background photon fields-both the cosmic microwave background… (more)

▼ Gamma ray photons, with energies >TeV propagating cosmological distances will be attenuated by pair production with diffuse extragalactic background photon fields-both the cosmic microwave background (CMB) radiation and the UV - far-IR extragalactic background light (EBL). The produced electron/positron pairs will subsequently inverse Compton scatter background photons up to GeV - TeV energies, and some of these upscattered photons may also initiate pair production in the formation of an electromagnetic cascade. If an intergalactic magnetic field (IGMF) exists on cosmological length scales of relevance to the cascade, it will deflect the electrons and positrons and will leave an imprint on the resulting spectral, angular, and temporal properties of the cascade radiation. The primary goal of this study was to constrain the properties of the IGMF using data from known sources of TeV gamma-rays.This thesis describes the construction of a high precision, 3-dimensional, particle-tracking Monte Carlo simulation code to model the intergalactic electromagnetic cascade, and uses it to systematically explore the effects of the IGMF on the cascades in multiple observational domains. We then compare the simulations with gamma-ray data from current generation ground-based gamma-ray instruments such as VERITAS, HESS, and MAGIC, sensitive to TeV-scale energies, as well as the Fermi satellite, sensitive to the GeV-scale.This novel technique of constraining the IGMF has rapidly emerged over the last decade as gamma-ray instruments have become more sensitive and as theoretical understanding of the cascade process has progressed. This emerging field has proven to be richly complex and we find that the data from current generation gamma-ray instruments do not allow for an unambiguous upper or lower limit to be placed on the IGMF at present. We do find it likely that the next generation ground based gamma-ray observatory, the Cherenkov Telescope Array (CTA) will be able to detect unambiguous signatures of gamma-ray cascading if the IGMF magnitude is within a certain range, and thus provide a robust constraint on IGMF properties.

Subjects/Keywords: Astrophysics; Physics; gamma-rays; Intergalactic magnetic fields

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APA (6^th Edition):

Arlen, T. (2013). Constraining the Intergalactic Magnetic Field Through its Imprint on Gamma Ray Data from Distant Sources. (Thesis). UCLA. Retrieved from http://www.escholarship.org/uc/item/0gv406rt

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Arlen, Timothy. “Constraining the Intergalactic Magnetic Field Through its Imprint on Gamma Ray Data from Distant Sources.” 2013. Thesis, UCLA. Accessed February 27, 2021. http://www.escholarship.org/uc/item/0gv406rt.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Arlen, Timothy. “Constraining the Intergalactic Magnetic Field Through its Imprint on Gamma Ray Data from Distant Sources.” 2013. Web. 27 Feb 2021.

Vancouver:

Arlen T. Constraining the Intergalactic Magnetic Field Through its Imprint on Gamma Ray Data from Distant Sources. [Internet] [Thesis]. UCLA; 2013. [cited 2021 Feb 27]. Available from: http://www.escholarship.org/uc/item/0gv406rt.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Arlen T. Constraining the Intergalactic Magnetic Field Through its Imprint on Gamma Ray Data from Distant Sources. [Thesis]. UCLA; 2013. Available from: http://www.escholarship.org/uc/item/0gv406rt

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of Exeter

17. Hawkes, G. Magnetic helicity flow in the Sun and heliosphere.

Degree: PhD, 2020, University of Exeter

URL: http://hdl.handle.net/10871/121154

► Magnetic helicity, the measure of entanglement within a magnetic field, has the capability to further our knowledge of the magnetic fields which are ubiquitous across… (more)

▼ Magnetic helicity, the measure of entanglement within a magnetic field, has the capability to further our knowledge of the magnetic fields which are ubiquitous across the physical universe. Discovered half a century ago by Lodewijk Woltjer in 1958, it was only given physical meaning by Keith Moffatt in 1969. Progress was initially slow due to the constraints on its calculation: it is assumed that the volume within which we wish to measure helicity does not have any magnetic field crossing its boundaries. But, in 1984, Mitchell Berger and George Field provided a resolution to this problem which allowed it to be applied to open astrophysical fields. From there, and particularly in the last two decades, interest in magnetic helicity has grown exponentially within the research community, resulting in this thesis. We will begin by providing a semi – formal introduction to the topic, in particular that of magnetohydrodynamics, which describes how a magnetic field and associated plasma co-interact. We provide a mathematical introduction to magnetic helicity, and demonstrate that unsolved problems remain in our understanding of the Sun's magnetic field that are associated with its magnetic helicity. With this knowledge in hand, we first tackle the topic of predicting the Solar Cycle, which has been an unachieved goal of the solar physics community for longer than we care to remember. We show that magnetic helicity, which is intrinsically linked to the emergence of sunspots, is a statistically stronger candidate for the predictor of activity than that of the polar field strength, which is the current 'best of the worst' of the known predictors. We then, for the first time, measure how much helicity is generated on the solar surface due to shear motions in a surface flux transport model, which is a method of modelling the magnetic field on the surface of the sun. We show that the results are not as obvious as we expect, and indeed that the flux of magnetic helicity within each hemisphere is carefully balanced between latitudes. We also provide an estimate of how much helicity is produced in a solar cycle, and correlate this with the dipole strength of that cycle. This is followed by the main result of the thesis: we demonstrate that helicity can be completely generalised for any physical system in terms of a two – point correlation, and fully described in terms of spatial scales and locality using wavelet analysis. In particular, we show that our generalised measure of helicity offers a physical meaning to this localisation. Our methods are demonstrated to have some notable advantages to that of Fourier analysis, which is shown to sometimes produce spurious results. Finally, we explore the hypothesis that the shape of a magnetic field domain can contribute to the magnetic helicity when using a toroidal – poloidal decomposition. Indeed, in some cases the asymmetry contains the entirety of the magnetic helicity, which we demonstrate numerically.

Subjects/Keywords: magnetic fields; helicity; sun; solar physics

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Hawkes, G. (2020). Magnetic helicity flow in the Sun and heliosphere. (Doctoral Dissertation). University of Exeter. Retrieved from http://hdl.handle.net/10871/121154

Chicago Manual of Style (16^th Edition):

Hawkes, G. “Magnetic helicity flow in the Sun and heliosphere.” 2020. Doctoral Dissertation, University of Exeter. Accessed February 27, 2021. http://hdl.handle.net/10871/121154.

MLA Handbook (7^th Edition):

Hawkes, G. “Magnetic helicity flow in the Sun and heliosphere.” 2020. Web. 27 Feb 2021.

Vancouver:

Hawkes G. Magnetic helicity flow in the Sun and heliosphere. [Internet] [Doctoral dissertation]. University of Exeter; 2020. [cited 2021 Feb 27]. Available from: http://hdl.handle.net/10871/121154.

Council of Science Editors:

Hawkes G. Magnetic helicity flow in the Sun and heliosphere. [Doctoral Dissertation]. University of Exeter; 2020. Available from: http://hdl.handle.net/10871/121154

Stellenbosch University

18. Doll, Stefan. Development of a magnetic intra-uterine manipulator.

Degree: MScEng, Mechanical and Mechatronic Engineering, 2012, Stellenbosch University

URL: http://hdl.handle.net/10019.1/19935

►

ENGLISH ABSTRACT: Uterine manipulation is integral to obtaining adequate access to the uterus during a laparoscopic procedure. A variety of mechanical manipulators have been developed… (more)

▼

ENGLISH ABSTRACT: Uterine manipulation is integral to obtaining adequate access to the uterus during a laparoscopic procedure. A variety of mechanical manipulators have been developed to aid the surgeon with the dissection of the uterus during laparoscopic hysterectomies. Limitations of existing manipulators are that they require an additional assistant during surgery, are expensive and may cause tissue trauma to the vaginal or cervical canal. This study introduces the novel concept of a magnetic uterine manipulator, intended to overcome existing devices’ shortcomings and enabling non-invasive uterine manipulation. The first goal of the study was to investigate the strengths and weaknesses of existing mechanical manipulators and compare them to those of a magnetic device. Analysis showed that a magnetic manipulator would not be able to compete in terms of the range of motion of existing devices. A limited anteriorsagittal rotation range of 60 was seen in the magnetic manipulator compared to a range of 140 in mechanical devices. However, the magnetic manipulator could eliminate the need for an extra assistant, is reusable and thus also more economical. The second goal was to investigate which type of setup would be most successful at effective uterine manipulation. Through concept analysis a cart-on-arch system was deemed most effective. To lift an effective load of 1 N over an air-gap of 150 mm rare-earth N38 Neodymium (NdFeBr) magnets showed the most promise as magnetic actuators. FEA (Finite Element Analysis) simulations of the magnetic setup were validated experimentally which produced an acceptable MAE (mean absolute error) of 0.15 N. Furthermore, a comparative simulation study of shielded and unshielded magnets was done which concluded that shielded magnets produce a slightly higher attraction force and would be safer to use due to less magnetic flux fringing. Thirdly and lastly, potential safety hazards and risks of using magnetic actuators in surgical environments were identified. The literature research revealed that connections between magnetic fields and health risks to patients have not been conclusively proven in clinical studies to date, but nonetheless, great care should be taken in situations where the patient has a pace-maker or orthopaedic implants, as these might interact with the magnetic field. Recommendations for future work include further research into the geometry and scaling effects of magnetic shielding as well as electromagnetic actuator design. Electromagnetic actuators could replace rare-earth magnets, if coil and cooling systems are optimized, resulting in magnets that can be reversed or switched off and which are therefore easier to control and safer to handle.

AFRIKAANSE OPSOMMING: Ontwikkeling van ’n Magnetiese Intra-Uteriene Manipuleerder Baarmoedermanipulasie is van uiterste belang om sodoende voldoende toegang te kry tot die baarmoeder gedurende ’n laparoskopiese prosedure. Daar is reeds ’n verskeidenheid meganiese manipuleerders…

Advisors/Committee Members: Scheffer, C., Stellenbosch University. Faculty of Engineering. Dept. of Mechanical and Mechatronic Engineering..

Subjects/Keywords: Mechatronic engineering; Magnetic fields – Health risks

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APA (6^th Edition):

Doll, S. (2012). Development of a magnetic intra-uterine manipulator. (Masters Thesis). Stellenbosch University. Retrieved from http://hdl.handle.net/10019.1/19935

Chicago Manual of Style (16^th Edition):

Doll, Stefan. “Development of a magnetic intra-uterine manipulator.” 2012. Masters Thesis, Stellenbosch University. Accessed February 27, 2021. http://hdl.handle.net/10019.1/19935.

MLA Handbook (7^th Edition):

Doll, Stefan. “Development of a magnetic intra-uterine manipulator.” 2012. Web. 27 Feb 2021.

Vancouver:

Doll S. Development of a magnetic intra-uterine manipulator. [Internet] [Masters thesis]. Stellenbosch University; 2012. [cited 2021 Feb 27]. Available from: http://hdl.handle.net/10019.1/19935.

Council of Science Editors:

Doll S. Development of a magnetic intra-uterine manipulator. [Masters Thesis]. Stellenbosch University; 2012. Available from: http://hdl.handle.net/10019.1/19935

Oregon State University

19. Anderson, Lee Roy. Numerical methods for variable permeability magnetostatic field problems.

Degree: PhD, General Science, 1969, Oregon State University

URL: http://hdl.handle.net/1957/45791

► Solutions to the variable permeability magnetostatic field problem are achieved in both rectangular and cylindrical coordinates for a wide variety of magnet geometries. The resulting… (more)

Subjects/Keywords: Magnetic fields – Measurement

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APA (6^th Edition):

Anderson, L. R. (1969). Numerical methods for variable permeability magnetostatic field problems. (Doctoral Dissertation). Oregon State University. Retrieved from http://hdl.handle.net/1957/45791

Chicago Manual of Style (16^th Edition):

Anderson, Lee Roy. “Numerical methods for variable permeability magnetostatic field problems.” 1969. Doctoral Dissertation, Oregon State University. Accessed February 27, 2021. http://hdl.handle.net/1957/45791.

MLA Handbook (7^th Edition):

Anderson, Lee Roy. “Numerical methods for variable permeability magnetostatic field problems.” 1969. Web. 27 Feb 2021.

Vancouver:

Anderson LR. Numerical methods for variable permeability magnetostatic field problems. [Internet] [Doctoral dissertation]. Oregon State University; 1969. [cited 2021 Feb 27]. Available from: http://hdl.handle.net/1957/45791.

Council of Science Editors:

Anderson LR. Numerical methods for variable permeability magnetostatic field problems. [Doctoral Dissertation]. Oregon State University; 1969. Available from: http://hdl.handle.net/1957/45791

University of Delaware

20. Tessein, Jeffrey A. Effect of coherent structures on energetic particle intensity in the solar wind.

Degree: PhD, University of Delaware, Department of Physics and Astronomy, 2015, University of Delaware

URL: http://udspace.udel.edu/handle/19716/17614

► Solar energetic particles in the solar wind are accelerated in both solar flares and shocks assocated with fast coronal mass ejections. They follow the interplanetary… (more)

▼ Solar energetic particles in the solar wind are accelerated in both solar flares and shocks assocated with fast coronal mass ejections. They follow the interplanetary magnetic field and, upon reaching Earth, have implications for space weather. Space weather affects astronaut health and orbiting equipment through radiation hazard and electrical infrastructure on the ground with ground induced currents. Economic im- pacts include disruption of GPS and redirection of commercial polar flights due to a dangerous radiation environment over the poles. By studying how these particles interact with the magnetic fields we can better predict onset times and diffusion of these events. We find, using superposed epoch analysis and conditional statisitics from spacecraft observations that there is a strong association between energetic particles in the solar wind and magnetic discontinuities. This may be related to turbulent dissipa- tion mechanisms in which coherent structures in the solar wind seem to be preferred sites of heating, plasma instabilites and dissipation. In the case of energetic particles, magnetic reconnection and transport in flux tubes are likely to play a role. Though we focus on data away from large shocks, trapping can occur in the downstream region of shocks due to the preponderance of compressive turbulence in these areas. This thesis lays the ground work for the results described above with an intro- duction to solar wind and heliospheric physics in Chapter 1. Chapter 2 is an intro- duction to the acceleration mechanisms that give rise to observed energetic particle events. Chapter 3 describes various data analysis techniques and statistics that are bread and butter when analyzing spacecraft data for turbulence and energetic particle studies. Chapter 4 is a digression that covers preliminary studies that were done on the side; scale dependent kurtosis, ergodic studies and initial conditions for simulations. Chapter 5 contains that central published results of this thesis, that there is a strong association between energetic particle intensity and magnetic discontinuties and that the correlation is can be attributed to transport and local acceleration. Advisors/Committee Members: Matthaeus, William H..

Subjects/Keywords: Solar energetic particles.; Solar wind.; Magnetic fields.

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APA (6^th Edition):

Tessein, J. A. (2015). Effect of coherent structures on energetic particle intensity in the solar wind. (Doctoral Dissertation). University of Delaware. Retrieved from http://udspace.udel.edu/handle/19716/17614

Chicago Manual of Style (16^th Edition):

Tessein, Jeffrey A. “Effect of coherent structures on energetic particle intensity in the solar wind.” 2015. Doctoral Dissertation, University of Delaware. Accessed February 27, 2021. http://udspace.udel.edu/handle/19716/17614.

MLA Handbook (7^th Edition):

Tessein, Jeffrey A. “Effect of coherent structures on energetic particle intensity in the solar wind.” 2015. Web. 27 Feb 2021.

Vancouver:

Tessein JA. Effect of coherent structures on energetic particle intensity in the solar wind. [Internet] [Doctoral dissertation]. University of Delaware; 2015. [cited 2021 Feb 27]. Available from: http://udspace.udel.edu/handle/19716/17614.

Council of Science Editors:

Tessein JA. Effect of coherent structures on energetic particle intensity in the solar wind. [Doctoral Dissertation]. University of Delaware; 2015. Available from: http://udspace.udel.edu/handle/19716/17614

University of Delaware

21. Subedi, Prachanda. Transport of charged particles in turbulent magnetic fields.

Degree: PhD, University of Delaware, Department of Physics and Astronomy, 2017, University of Delaware

URL: http://udspace.udel.edu/handle/19716/22622

► Magnetic fields permeate the Universe. They are found in planets, stars, galaxies, and the intergalactic medium. The magnetic field found in these astrophysical systems are… (more)

▼ Magnetic fields permeate the Universe. They are found in planets, stars, galaxies, and the intergalactic medium. The magnetic field found in these astrophysical systems are usually chaotic, disordered, and turbulent. The investigation of the transport of cosmic rays in magnetic turbulence is a subject of considerable interest. ☐ One of the important aspects of cosmic ray transport is to understand their diffusive behavior and to calculate the diffusion coefficient in the presence of these turbulent fields. Research has most frequently concentrated on determining the diffusion coefficient in the presence of a mean magnetic field. Here, we will particularly focus on calculating diffusion coefficients of charged particles and magnetic field lines in a fully three-dimensional isotropic turbulent magnetic field with no mean field, which may be pertinent to many astrophysical situations. ☐ For charged particles in isotropic turbulence we identify different ranges of particle energy depending upon the ratio of the Larmor radius of the charged particle to the characteristic outer length scale of the turbulence. Different theoretical models are proposed to calculate the diffusion coefficient, each applicable to a distinct range of particle energies. The theoretical ideas are tested against results of detailed numerical experiments using Monte-Carlo simulations of particle propagation in stochastic magnetic fields. ☐ We also discuss two different methods of generating random magnetic field to study charged particle propagation using numerical simulation. One method is the usual way of generating random fields with a specified power law in wavenumber space, using Gaussian random variables. Turbulence, however, is non-Gaussian, with variability that comes in bursts called intermittency. We therefore devise a way to generate synthetic intermittent fields which have many properties of realistic turbulence. Possible applications of such synthetically generated intermittent fields are discussed. Advisors/Committee Members: Matthaeus, William H..

Subjects/Keywords: Pure sciences; Charged particles; Turbulent magnetic fields

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APA (6^th Edition):

Subedi, P. (2017). Transport of charged particles in turbulent magnetic fields. (Doctoral Dissertation). University of Delaware. Retrieved from http://udspace.udel.edu/handle/19716/22622

Chicago Manual of Style (16^th Edition):

Subedi, Prachanda. “Transport of charged particles in turbulent magnetic fields.” 2017. Doctoral Dissertation, University of Delaware. Accessed February 27, 2021. http://udspace.udel.edu/handle/19716/22622.

MLA Handbook (7^th Edition):

Subedi, Prachanda. “Transport of charged particles in turbulent magnetic fields.” 2017. Web. 27 Feb 2021.

Vancouver:

Subedi P. Transport of charged particles in turbulent magnetic fields. [Internet] [Doctoral dissertation]. University of Delaware; 2017. [cited 2021 Feb 27]. Available from: http://udspace.udel.edu/handle/19716/22622.

Council of Science Editors:

Subedi P. Transport of charged particles in turbulent magnetic fields. [Doctoral Dissertation]. University of Delaware; 2017. Available from: http://udspace.udel.edu/handle/19716/22622

Columbia University

22. Alford, Jason. Inferences from Surface Thermal Emission of Young Neutron Stars.

Degree: 2020, Columbia University

URL: https://doi.org/10.7916/d8-gr5k-6h13

► We consider the question of the magnetic field configuration of central compact objects (CCOs), specifically if their observed spectra allow uniform surface temperatures and carbon… (more)

▼ We consider the question of the magnetic field configuration of central compact objects (CCOs), specifically if their observed spectra allow uniform surface temperatures and carbon atmospheres. Although it is theoretically plausible that young hot neutron stars will deplete their hydrogen and helium atmospheres through diffusive nuclear burning, we find that there is no strong observational evidence to suggest that any particular CCO has a uniform temperature carbon atmosphere. In fact, they all may have small hot spots, similar to what we have measured on the surface of RX J0822−4300, and what has been observed in the cases of two other CCOs, 1E 1207.4−5209 and PSR J1852+0040. We find it is likely that most CCOs have small magnetic inclination angles. We also study the magnetic field configurations of two particular young neutron stars through general relativistic modeling of the X-ray light curves produced by their thermal surface emission. In particular, we have analyzed over a decade of XMM-Newton observations of the central compact object RX J0822−4300 and also the transient magnetar XTEJ1810−197. We show that the CCO RX J0822−4300 has two heated regions with very dif-ferent sizes and temperatures, and we measure a significant deviation angle from a purelyantipodal geometry. This measurement can inform theoretical models of the strength and geometry of the crustal magnetic fields that conduct heat to toward these hot spots. We measure the size, temperature, angular emission pattern and viewing geometry toward the heated surface regions of the magnetar XTE J1810−197 in the years following its 2003 outburst. We demonstrate that, after the size and the temperature of the heated region shrank from what was measured in the initial outburst, the magnetar eventually entered a steady state with the hot spot luminosity powered by magnetic field decay. We find that the magnitude of the flux from the whole surface of XTE J1810−197, combined with several distance estimates, indicates that the mass of XTE J1810−197 must be significantly larger than the canonical 1.4 solar mass neutron star.

Subjects/Keywords: Neutron stars; Astrophysics; Magnetic fields; Stars – Temperature

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APA (6^th Edition):

Alford, J. (2020). Inferences from Surface Thermal Emission of Young Neutron Stars. (Doctoral Dissertation). Columbia University. Retrieved from https://doi.org/10.7916/d8-gr5k-6h13

Chicago Manual of Style (16^th Edition):

Alford, Jason. “Inferences from Surface Thermal Emission of Young Neutron Stars.” 2020. Doctoral Dissertation, Columbia University. Accessed February 27, 2021. https://doi.org/10.7916/d8-gr5k-6h13.

MLA Handbook (7^th Edition):

Alford, Jason. “Inferences from Surface Thermal Emission of Young Neutron Stars.” 2020. Web. 27 Feb 2021.

Vancouver:

Alford J. Inferences from Surface Thermal Emission of Young Neutron Stars. [Internet] [Doctoral dissertation]. Columbia University; 2020. [cited 2021 Feb 27]. Available from: https://doi.org/10.7916/d8-gr5k-6h13.

Council of Science Editors:

Alford J. Inferences from Surface Thermal Emission of Young Neutron Stars. [Doctoral Dissertation]. Columbia University; 2020. Available from: https://doi.org/10.7916/d8-gr5k-6h13

University of Cambridge

23. Wood, Toby. The solar tachocline: a self-consistent model of magnetic confinement.

Degree: PhD, 2011, University of Cambridge

URL: http://www.dspace.cam.ac.uk/handle/1810/230114https://www.repository.cam.ac.uk/bitstream/1810/230114/2/license.txt ; https://www.repository.cam.ac.uk/bitstream/1810/230114/3/tsw-thesis-final-online.pdf.txt ; https://www.repository.cam.ac.uk/bitstream/1810/230114/5/tsw-thesis-final-online.pdf.txt ; https://www.repository.cam.ac.uk/bitstream/1810/230114/6/tsw-thesis-final-online.pdf.jpg

► In this dissertation we consider the dynamics of the solar interior, with particular focus on angular momentum balance and magnetic field confinement within the tachocline.… (more)

Subjects/Keywords: Heliophysics; Solar rotation; Magnetic fields; Solar tachocline

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APA (6^th Edition):

Wood, T. (2011). The solar tachocline: a self-consistent model of magnetic confinement. (Doctoral Dissertation). University of Cambridge. Retrieved from http://www.dspace.cam.ac.uk/handle/1810/230114https://www.repository.cam.ac.uk/bitstream/1810/230114/2/license.txt ; https://www.repository.cam.ac.uk/bitstream/1810/230114/3/tsw-thesis-final-online.pdf.txt ; https://www.repository.cam.ac.uk/bitstream/1810/230114/5/tsw-thesis-final-online.pdf.txt ; https://www.repository.cam.ac.uk/bitstream/1810/230114/6/tsw-thesis-final-online.pdf.jpg

Chicago Manual of Style (16^th Edition):

Wood, Toby. “The solar tachocline: a self-consistent model of magnetic confinement.” 2011. Doctoral Dissertation, University of Cambridge. Accessed February 27, 2021. http://www.dspace.cam.ac.uk/handle/1810/230114https://www.repository.cam.ac.uk/bitstream/1810/230114/2/license.txt ; https://www.repository.cam.ac.uk/bitstream/1810/230114/3/tsw-thesis-final-online.pdf.txt ; https://www.repository.cam.ac.uk/bitstream/1810/230114/5/tsw-thesis-final-online.pdf.txt ; https://www.repository.cam.ac.uk/bitstream/1810/230114/6/tsw-thesis-final-online.pdf.jpg.

MLA Handbook (7^th Edition):

Wood, Toby. “The solar tachocline: a self-consistent model of magnetic confinement.” 2011. Web. 27 Feb 2021.

Vancouver:

Wood T. The solar tachocline: a self-consistent model of magnetic confinement. [Internet] [Doctoral dissertation]. University of Cambridge; 2011. [cited 2021 Feb 27]. Available from: http://www.dspace.cam.ac.uk/handle/1810/230114https://www.repository.cam.ac.uk/bitstream/1810/230114/2/license.txt ; https://www.repository.cam.ac.uk/bitstream/1810/230114/3/tsw-thesis-final-online.pdf.txt ; https://www.repository.cam.ac.uk/bitstream/1810/230114/5/tsw-thesis-final-online.pdf.txt ; https://www.repository.cam.ac.uk/bitstream/1810/230114/6/tsw-thesis-final-online.pdf.jpg.

Council of Science Editors:

Wood T. The solar tachocline: a self-consistent model of magnetic confinement. [Doctoral Dissertation]. University of Cambridge; 2011. Available from: http://www.dspace.cam.ac.uk/handle/1810/230114https://www.repository.cam.ac.uk/bitstream/1810/230114/2/license.txt ; https://www.repository.cam.ac.uk/bitstream/1810/230114/3/tsw-thesis-final-online.pdf.txt ; https://www.repository.cam.ac.uk/bitstream/1810/230114/5/tsw-thesis-final-online.pdf.txt ; https://www.repository.cam.ac.uk/bitstream/1810/230114/6/tsw-thesis-final-online.pdf.jpg

University of Oxford

24. Woodward, J. R. The effect of magnetic fields in chemistry and biology.

Degree: PhD, 1997, University of Oxford

URL: http://ora.ox.ac.uk/objects/uuid:2a881ed6-77a9-4e5f-95de-9974ac9e18e7 ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.389179

► This thesis is concerned with the effect of static and oscillatory magnetic fields on the yield of radical recombination reactions and the proposal that such… (more)

Subjects/Keywords: 530.41; Magnetic fields

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APA (6^th Edition):

Woodward, J. R. (1997). The effect of magnetic fields in chemistry and biology. (Doctoral Dissertation). University of Oxford. Retrieved from http://ora.ox.ac.uk/objects/uuid:2a881ed6-77a9-4e5f-95de-9974ac9e18e7 ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.389179

Chicago Manual of Style (16^th Edition):

Woodward, J R. “The effect of magnetic fields in chemistry and biology.” 1997. Doctoral Dissertation, University of Oxford. Accessed February 27, 2021. http://ora.ox.ac.uk/objects/uuid:2a881ed6-77a9-4e5f-95de-9974ac9e18e7 ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.389179.

MLA Handbook (7^th Edition):

Woodward, J R. “The effect of magnetic fields in chemistry and biology.” 1997. Web. 27 Feb 2021.

Vancouver:

Woodward JR. The effect of magnetic fields in chemistry and biology. [Internet] [Doctoral dissertation]. University of Oxford; 1997. [cited 2021 Feb 27]. Available from: http://ora.ox.ac.uk/objects/uuid:2a881ed6-77a9-4e5f-95de-9974ac9e18e7 ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.389179.

Council of Science Editors:

Woodward JR. The effect of magnetic fields in chemistry and biology. [Doctoral Dissertation]. University of Oxford; 1997. Available from: http://ora.ox.ac.uk/objects/uuid:2a881ed6-77a9-4e5f-95de-9974ac9e18e7 ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.389179

Michigan State University

25. Hanawa, Hiroji. The magnetic field measurement for the K500 cyclotron.

Degree: MS, Department of Electrical Engineering and Systems Science, 1984, Michigan State University

URL: http://etd.lib.msu.edu/islandora/object/etd:25255

Subjects/Keywords: Cyclotrons; Magnetic fields

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APA (6^th Edition):

Hanawa, H. (1984). The magnetic field measurement for the K500 cyclotron. (Masters Thesis). Michigan State University. Retrieved from http://etd.lib.msu.edu/islandora/object/etd:25255

Chicago Manual of Style (16^th Edition):

Hanawa, Hiroji. “The magnetic field measurement for the K500 cyclotron.” 1984. Masters Thesis, Michigan State University. Accessed February 27, 2021. http://etd.lib.msu.edu/islandora/object/etd:25255.

MLA Handbook (7^th Edition):

Hanawa, Hiroji. “The magnetic field measurement for the K500 cyclotron.” 1984. Web. 27 Feb 2021.

Vancouver:

Hanawa H. The magnetic field measurement for the K500 cyclotron. [Internet] [Masters thesis]. Michigan State University; 1984. [cited 2021 Feb 27]. Available from: http://etd.lib.msu.edu/islandora/object/etd:25255.

Council of Science Editors:

Hanawa H. The magnetic field measurement for the K500 cyclotron. [Masters Thesis]. Michigan State University; 1984. Available from: http://etd.lib.msu.edu/islandora/object/etd:25255

Montana State University

26. Munoz-Jaramillo, Andres. Towards better constrained models of the solar magnetic cycle.

Degree: PhD, College of Letters & Science, 2010, Montana State University

URL: https://scholarworks.montana.edu/xmlui/handle/1/1919

► The best tools we have for understanding the origin of solar magnetic variability are kinematic dynamo models. During the last decade, this type of models… (more)

▼ The best tools we have for understanding the origin of solar magnetic variability are kinematic dynamo models. During the last decade, this type of models has seen a continuous evolution and has become increasingly successful at reproducing solar cycle characteristics. The basic ingredients of these models are: the solar differential rotation - which acts as the main source of energy for the system by shearing the magnetic field; the meridional circulation - which plays a crucial role in magnetic field transport; the turbulent diffusivity - which attempts to capture the effect of convective turbulence on the large scale magnetic field; and the poloidal field source - which closes the cycle by regenerating the poloidal magnetic field. However, most of these ingredients remain poorly constrained which allows one to obtain solar-like solutions by "tuning" the input parameters, leading to controversy regarding which parameter set is more appropriate. In this thesis we revisit each of those ingredients in an attempt to constrain them better by using observational data and theoretical considerations, reducing the amount of free parameters in the model. For the meridional flow and differential rotation we use helioseismic data to constrain free parameters and find that the differential rotation is well determined, but the available data can only constrain the latitudinal dependence of the meridional flow. For the turbulent magnetic diffusivity we show that combining mixing-length theory estimates with magnetic quenching allows us to obtain viable magnetic cycles and that the commonly used diffusivity profiles can be understood as a spatiotemporal average of this process. For the poloidal source we introduce a more realistic way of modeling active region emergence and decay and find that this resolves existing discrepancies between kinematic dynamo models and surface flux transport simulations. We also study the physical mechanisms behind the unusually long minimum of cycle 23 and find it to be tied to changes in the meridional flow. Finally, by carefully constraining the system through surface magnetic field observations, we find that what is believed to be the primary source of poloidal field (also known as Babckock-Leigthon mechanism) may not be enough to sustain the solar magnetic cycle. Advisors/Committee Members: Chairperson, Graduate Committee: Petrus Martens (advisor).

Subjects/Keywords: Solar magnetic fields.

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APA (6^th Edition):

Munoz-Jaramillo, A. (2010). Towards better constrained models of the solar magnetic cycle. (Doctoral Dissertation). Montana State University. Retrieved from https://scholarworks.montana.edu/xmlui/handle/1/1919

Chicago Manual of Style (16^th Edition):

Munoz-Jaramillo, Andres. “Towards better constrained models of the solar magnetic cycle.” 2010. Doctoral Dissertation, Montana State University. Accessed February 27, 2021. https://scholarworks.montana.edu/xmlui/handle/1/1919.

MLA Handbook (7^th Edition):

Munoz-Jaramillo, Andres. “Towards better constrained models of the solar magnetic cycle.” 2010. Web. 27 Feb 2021.

Vancouver:

Munoz-Jaramillo A. Towards better constrained models of the solar magnetic cycle. [Internet] [Doctoral dissertation]. Montana State University; 2010. [cited 2021 Feb 27]. Available from: https://scholarworks.montana.edu/xmlui/handle/1/1919.

Council of Science Editors:

Munoz-Jaramillo A. Towards better constrained models of the solar magnetic cycle. [Doctoral Dissertation]. Montana State University; 2010. Available from: https://scholarworks.montana.edu/xmlui/handle/1/1919

Montana State University

27. Eckberg, Jon Thomas. Network flux transport: concept and application to solar magnetism.

Degree: MS, College of Letters & Science, 2019, Montana State University

URL: https://scholarworks.montana.edu/xmlui/handle/1/15768

► We have developed a method to efficiently simulate the dynamics of the magnetic flux in the solar network. We call this method Network Flux Transport… (more)

Subjects/Keywords: Solar magnetic fields.; Dynamics.; Simulation methods.

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APA (6^th Edition):

Eckberg, J. T. (2019). Network flux transport: concept and application to solar magnetism. (Masters Thesis). Montana State University. Retrieved from https://scholarworks.montana.edu/xmlui/handle/1/15768

Chicago Manual of Style (16^th Edition):

Eckberg, Jon Thomas. “Network flux transport: concept and application to solar magnetism.” 2019. Masters Thesis, Montana State University. Accessed February 27, 2021. https://scholarworks.montana.edu/xmlui/handle/1/15768.

MLA Handbook (7^th Edition):

Eckberg, Jon Thomas. “Network flux transport: concept and application to solar magnetism.” 2019. Web. 27 Feb 2021.

Vancouver:

Eckberg JT. Network flux transport: concept and application to solar magnetism. [Internet] [Masters thesis]. Montana State University; 2019. [cited 2021 Feb 27]. Available from: https://scholarworks.montana.edu/xmlui/handle/1/15768.

Council of Science Editors:

Eckberg JT. Network flux transport: concept and application to solar magnetism. [Masters Thesis]. Montana State University; 2019. Available from: https://scholarworks.montana.edu/xmlui/handle/1/15768

Montana State University

28. Tarr, Lucas Adrian. Energetic consequences of flux emergence.

Degree: PhD, College of Letters & Science, 2013, Montana State University

URL: https://scholarworks.montana.edu/xmlui/handle/1/2917

► When magnetic field in the solar convection zone buoyantly rises to pierce the visible solar surface (photosphere), the atmosphere (corona) above this surface must respond… (more)

Subjects/Keywords: Cosmic magnetic fields.; Solar energy.; Sun Corona.

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APA (6^th Edition):

Tarr, L. A. (2013). Energetic consequences of flux emergence. (Doctoral Dissertation). Montana State University. Retrieved from https://scholarworks.montana.edu/xmlui/handle/1/2917

Chicago Manual of Style (16^th Edition):

Tarr, Lucas Adrian. “Energetic consequences of flux emergence.” 2013. Doctoral Dissertation, Montana State University. Accessed February 27, 2021. https://scholarworks.montana.edu/xmlui/handle/1/2917.

MLA Handbook (7^th Edition):

Tarr, Lucas Adrian. “Energetic consequences of flux emergence.” 2013. Web. 27 Feb 2021.

Vancouver:

Tarr LA. Energetic consequences of flux emergence. [Internet] [Doctoral dissertation]. Montana State University; 2013. [cited 2021 Feb 27]. Available from: https://scholarworks.montana.edu/xmlui/handle/1/2917.

Council of Science Editors:

Tarr LA. Energetic consequences of flux emergence. [Doctoral Dissertation]. Montana State University; 2013. Available from: https://scholarworks.montana.edu/xmlui/handle/1/2917

Montana State University

29. Malanushenko, Anna Viktorovna. Twist in coronal magnetic fields.

Degree: PhD, College of Letters & Science, 2010, Montana State University

URL: https://scholarworks.montana.edu/xmlui/handle/1/1780

► Twist of magnetic field is believed to play important role in driving instabilities that result in eruptive events on the Sun. This thesis provides different… (more)

▼ Twist of magnetic field is believed to play important role in driving instabilities that result in eruptive events on the Sun. This thesis provides different methods to measure twist in the solar corona. First, given a model of coronal field, twist of a magnetic domain (i.e., a volume that contains all field lines connecting two regions of interest in the photosphere) is well studied for cases when the domain is a thin cylinder. For cases when such approximation is inapplicable a generalization of twist can be derived from a quantity called additive self-helicity. I develop explicit numerical methods to compute generalized twist. I also demonstrate that such a quantity sets a threshold on kink instability like the traditional twist does for thin cylinders. In a more realistic scenario, coronal magnetic field is not known and so neither is its helicity. There are two principal methods to overcome this problem. The first is to integrate helicity flux across the photosphere (as helicity is believed to be approximately conserved in the corona) using magnetic field on Sun's surface. There is little published evidence as yet that coronal helicity indeed corresponds to its integrated photospheric flux. The second is to extrapolate the coronal magnetic field using surface measurements as boundary conditions and use this extrapolation for helicity computation; for fields with complicated structure such extrapolations are extremely challenging and suffer from major drawbacks. I develop a method to estimate twist of coronal fields without attempting complicated extrapolations or studying helicity flux. The method builds a simple uniformly-twisted magnetic field and adjusts its properties until there is one line in this field that matches one coronal loop; this is repeated for all evident coronal loops resulting in twist measurements for each individual loop. I use this method to demonstrate that the rate of change of twist in the solar corona is indeed approximately equal to the one derived from photospheric helicity flux. The results of this dissertation are useful for better understanding of magnetic topology in general. They are also extremely promising for extrapolating coronal magnetic fields. Measurements of coronal twist might aid in predicting magnetic instabilities. Advisors/Committee Members: Chairperson, Graduate Committee: Dana W. Longcope (advisor).

Subjects/Keywords: Magnetic fields.; Topology.

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APA (6^th Edition):

Malanushenko, A. V. (2010). Twist in coronal magnetic fields. (Doctoral Dissertation). Montana State University. Retrieved from https://scholarworks.montana.edu/xmlui/handle/1/1780

Chicago Manual of Style (16^th Edition):

Malanushenko, Anna Viktorovna. “Twist in coronal magnetic fields.” 2010. Doctoral Dissertation, Montana State University. Accessed February 27, 2021. https://scholarworks.montana.edu/xmlui/handle/1/1780.

MLA Handbook (7^th Edition):

Malanushenko, Anna Viktorovna. “Twist in coronal magnetic fields.” 2010. Web. 27 Feb 2021.

Vancouver:

Malanushenko AV. Twist in coronal magnetic fields. [Internet] [Doctoral dissertation]. Montana State University; 2010. [cited 2021 Feb 27]. Available from: https://scholarworks.montana.edu/xmlui/handle/1/1780.

Council of Science Editors:

Malanushenko AV. Twist in coronal magnetic fields. [Doctoral Dissertation]. Montana State University; 2010. Available from: https://scholarworks.montana.edu/xmlui/handle/1/1780

Montana State University

30. Scott, Jason Terrence. Multi-instrument observations of coronal loops.

Degree: PhD, College of Letters & Science, 2012, Montana State University

URL: https://scholarworks.montana.edu/xmlui/handle/1/2228

► This document exhibits results of analysis from data collected with multiple EUV satellites (SOHO, TRACE, STEREO, Hinode, and SDO). The focus is the detailed observation… (more)

Subjects/Keywords: Spectrum analysis; Imaging systems; Solar magnetic fields

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APA (6^th Edition):

Scott, J. T. (2012). Multi-instrument observations of coronal loops. (Doctoral Dissertation). Montana State University. Retrieved from https://scholarworks.montana.edu/xmlui/handle/1/2228

Chicago Manual of Style (16^th Edition):

Scott, Jason Terrence. “Multi-instrument observations of coronal loops.” 2012. Doctoral Dissertation, Montana State University. Accessed February 27, 2021. https://scholarworks.montana.edu/xmlui/handle/1/2228.

MLA Handbook (7^th Edition):

Scott, Jason Terrence. “Multi-instrument observations of coronal loops.” 2012. Web. 27 Feb 2021.

Vancouver:

Scott JT. Multi-instrument observations of coronal loops. [Internet] [Doctoral dissertation]. Montana State University; 2012. [cited 2021 Feb 27]. Available from: https://scholarworks.montana.edu/xmlui/handle/1/2228.

Council of Science Editors:

Scott JT. Multi-instrument observations of coronal loops. [Doctoral Dissertation]. Montana State University; 2012. Available from: https://scholarworks.montana.edu/xmlui/handle/1/2228

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