THE PROPAGATION OF ENERGETIC PARTICLES IN FINITE TEMPERATURE ASTROPHYSICAL PLASMAS.

Persistent Link:
http://hdl.handle.net/10150/184791
Title:
THE PROPAGATION OF ENERGETIC PARTICLES IN FINITE TEMPERATURE ASTROPHYSICAL PLASMAS.
Author:
DAVILA, JOSEPH MICHAEL.
Issue Date:
1982
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
Solutions to the dispersion relation for waves propagating parallel to the static magnetic field in a plasma of arbitrary β are obtained. (β is the ratio of thermal to magnetic pressure.) Resonant scattering by these waves is evaluated. It is found that the magnetostatic approximation, used extensively in the past, breaks down for particles with pitch angles near 90°, and one must consider the more complicated process of particle scattering in electromagnetic turbulence. Many aspects of particle propagation in a finite temperature plasma can be discussed without assuming magnetostatic turbulence. This is accomplished by using a graphical method to obtain the solutions of the resonance condition. Results show that in a high β plasma, wave damping causes a gap, or hole, in μ-space where the resonant particle scattering rate is severely depressed. It is found that only high energy (γ ≥10⁵) electrons can be trapped within a typical supernova remnant. When the notion of electromagnetic resonance is applied to particle propagation in the interplanetary β ≤ 1) plasma, it is found that significant modifications to the conventional scattering picture must be made. It is found that a resonance gap exists which is similar to the one in a high β plasma. For electrons, this gap provides a natural explanation for scatter-free events. Theory predicts that these events should occur for kinetic energies T ≤ 300 keV while observations indicate that the majority have T ≤ 500 keV. For protons and energetic electrons, the scattering mean free path is critically dependent on the non-resonant scattering rate for particles within the gap. This fact provides a way to resolve the well known discrepancy between the theoretical and observational values for the mean free path, λ.
Type:
text; Dissertation-Reproduction (electronic)
Keywords:
Space plasmas.; Scattering (Physics)
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Astronomy; Graduate College
Degree Grantor:
University of Arizona
Advisor:
Scott, John

Full metadata record

DC FieldValue Language
dc.language.isoenen_US
dc.titleTHE PROPAGATION OF ENERGETIC PARTICLES IN FINITE TEMPERATURE ASTROPHYSICAL PLASMAS.en_US
dc.creatorDAVILA, JOSEPH MICHAEL.en_US
dc.contributor.authorDAVILA, JOSEPH MICHAEL.en_US
dc.date.issued1982en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractSolutions to the dispersion relation for waves propagating parallel to the static magnetic field in a plasma of arbitrary β are obtained. (β is the ratio of thermal to magnetic pressure.) Resonant scattering by these waves is evaluated. It is found that the magnetostatic approximation, used extensively in the past, breaks down for particles with pitch angles near 90°, and one must consider the more complicated process of particle scattering in electromagnetic turbulence. Many aspects of particle propagation in a finite temperature plasma can be discussed without assuming magnetostatic turbulence. This is accomplished by using a graphical method to obtain the solutions of the resonance condition. Results show that in a high β plasma, wave damping causes a gap, or hole, in μ-space where the resonant particle scattering rate is severely depressed. It is found that only high energy (γ ≥10⁵) electrons can be trapped within a typical supernova remnant. When the notion of electromagnetic resonance is applied to particle propagation in the interplanetary β ≤ 1) plasma, it is found that significant modifications to the conventional scattering picture must be made. It is found that a resonance gap exists which is similar to the one in a high β plasma. For electrons, this gap provides a natural explanation for scatter-free events. Theory predicts that these events should occur for kinetic energies T ≤ 300 keV while observations indicate that the majority have T ≤ 500 keV. For protons and energetic electrons, the scattering mean free path is critically dependent on the non-resonant scattering rate for particles within the gap. This fact provides a way to resolve the well known discrepancy between the theoretical and observational values for the mean free path, λ.en_US
dc.typetexten_US
dc.typeDissertation-Reproduction (electronic)en_US
dc.subjectSpace plasmas.en_US
dc.subjectScattering (Physics)en_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineAstronomyen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorScott, Johnen_US
dc.identifier.proquest8217406en_US
dc.identifier.oclc681955284en_US
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