A short study of the plasma sheet in the geomagnetic tail

dc.contributor.advisorWolf, Richard A.
dc.creatorRich, Frederick Joseph
dc.date.accessioned2016-04-22T21:59:54Z
dc.date.available2016-04-22T21:59:54Z
dc.date.issued1972
dc.description.abstractThis thesis approaches two theoretical problems associated with the plasma sheet in the geomagnetic tail. The first problem is the structure of the plasma sheet. It is approached by considering the plasma sheet as a sheet of collision-less plasma with isotropic gas pressure that is in a state of balance between the macroscopic forces. Only the forces due to the plasma gas pressure and the magnetic field forces are considered. The calculations are done in two dimensions by neglecting any Ysm component of the geomagnetic tail field. The discussion of force balance argues that, unless there is a significant contribution to the forces in the tail from some neglected source, the normal component of field must be on the average positive in all parts of the plasma sheet. A model configuration is computed as an example of force balance and yield the relation Bzo /(dp * Bxx) = 0.72 where Bzo is the normal component of field in the center of the sheet (gammas), dp is the sheet half thickness (Re), and Bxx is the radial gradient of the external field strength Also, the z-variation of the plasma sheet field strength show no presence of a neutral sheet, a thin (~10 to the 3rd km) reversing layer with a field strength of several gammas on either side, within the plasma sheet. Indeed, a neutral sheet may be inconsistent with a force balance plasma sheet unless additions balancing forces or anisotropies of the plasma pressure are considered. The second problem is a study of the effect of a geomagnetic-like neutral sheet, a thin current sheet where ionic, and maybe electronic, motions are non-adiabatic, on plasma. The results of previous studies by Speiser are found to be basically correct but limited. It is shown that the energy, pitch angle and phase angle dependence of the change in pitch angle of ions traveling through the neutral sheet makes it unlikely that the neutral sheet is responsible for direct precipitation of plasma sheet ions into the auroral ionosphere as suggested by Speiser, The effective conductivities of the neutral sheet needed to describe the neutral sheet with MHD are found to be useful but accurate only as a rough estimate of the time effective conductivity which may be a function of position and other parameters.
dc.format.digitalOriginreformatted digitalen_US
dc.format.extent107 ppen_US
dc.identifier.callnoThesis SP.SCI. 1972 Richen_US
dc.identifier.citationRich, Frederick Joseph. "A short study of the plasma sheet in the geomagnetic tail." (1972) Master’s Thesis, Rice University. <a href="https://hdl.handle.net/1911/90135">https://hdl.handle.net/1911/90135</a>.
dc.identifier.digitalRICE1171en_US
dc.identifier.urihttps://hdl.handle.net/1911/90135
dc.language.isoeng
dc.rightsCopyright is held by the author, unless otherwise indicated. Permission to reuse, publish, or reproduce the work beyond the bounds of fair use or other exemptions to copyright law must be obtained from the copyright holder.
dc.titleA short study of the plasma sheet in the geomagnetic tail
dc.typeThesis
dc.type.materialText
thesis.degree.departmentSpace Science
thesis.degree.disciplineNatural Sciences
thesis.degree.grantorRice University
thesis.degree.levelMasters
thesis.degree.nameMaster of Science
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