Variation of the plasma-sheet polytropic index along the midnight meridian in a finite-width magnetotail. Technical report

Spence, H E; Kivelson, M G

Title: Variation of the plasma-sheet polytropic index along the midnight meridian in a finite-width magnetotail. Technical report

Full Record
Other Related Research

Abstract

The polytropic index is obtained as a function of distance along the midnight meridian in the terrestrial magnetotail. As our purpose is to establish the effects of the finite width of the magnetotail, we use a simple theoretical model of plasma sheet convection, i.e., two-dimensional field structure and adiabatic inward convection of a uniform distant tail source. Particle orbits are treated independently for portions of the phase space distribution on shells of constant energy. On the midnight meridian, the moments of the distribution are parameterized by tau, the ratio of half the cross-tail potential energy to the characteristic Maxwellian energy of a distant down-tail plasma source. We infer from the model the plasma pressure, P, and the number density, n, along the midnight meridian as a function of tau. P and n define locally an effective polytropic index. Gamma ranges between 5/3 and 1, depending on the value of tau and on geocentric distance. The qualitative differences between the recent empirical determinations of the polytropic index by Baumjohann and Paschmann and Huang et al. may be accounted for in part by this simple model.

Authors:: Spence, H E; Kivelson, M G

Publication Date:: Wed Aug 15 00:00:00 EDT 1990

Research Org.:: Aerospace Corp., El Segundo, CA (USA). Laboratory Operations

OSTI Identifier:: 6046665

Report Number(s):: AD-A-225948/9/XAB; TR-0089(4940-06)-8
CNN: F04701-88-C-0089

Resource Type:: Technical Report

Country of Publication:: United States

Language:: English

Subject:: 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; PLASMA SHEET; CONVECTION; MATHEMATICAL MODELS; CHARGE DENSITY; DISTANCE; EARTH MAGNETOSPHERE; MAGNETOTAIL; MAXWELL EQUATIONS; PLASMA; PROGRESS REPORT; RADIATION PRESSURE; SIZE; DIFFERENTIAL EQUATIONS; DOCUMENT TYPES; EARTH ATMOSPHERE; ENERGY TRANSFER; EQUATIONS; HEAT TRANSFER; MASS TRANSFER; PARTIAL DIFFERENTIAL EQUATIONS; 640201* - Atmospheric Physics- Auroral, Ionospheric, & Magetospheric Phenomena

Citation Formats


                    Spence, H E, and Kivelson, M G. Variation of the plasma-sheet polytropic index along the midnight meridian in a finite-width magnetotail. Technical report.  United States: N. p., 1990. 
        Web.

Copy to clipboard


                    Spence, H E, & Kivelson, M G. Variation of the plasma-sheet polytropic index along the midnight meridian in a finite-width magnetotail. Technical report.  United States.

Copy to clipboard


                    Spence, H E, and Kivelson, M G. 1990.  
        "Variation of the plasma-sheet polytropic index along the midnight meridian in a finite-width magnetotail. Technical report".  United States.

Copy to clipboard


                    
@article{osti_6046665,

  title        = {Variation of the plasma-sheet polytropic index along the midnight meridian in a finite-width magnetotail. Technical report},

  author       = {Spence, H E and Kivelson, M G},

  abstractNote = {The polytropic index is obtained as a function of distance along the midnight meridian in the terrestrial magnetotail. As our purpose is to establish the effects of the finite width of the magnetotail, we use a simple theoretical model of plasma sheet convection, i.e., two-dimensional field structure and adiabatic inward convection of a uniform distant tail source. Particle orbits are treated independently for portions of the phase space distribution on shells of constant energy. On the midnight meridian, the moments of the distribution are parameterized by tau, the ratio of half the cross-tail potential energy to the characteristic Maxwellian energy of a distant down-tail plasma source. We infer from the model the plasma pressure, P, and the number density, n, along the midnight meridian as a function of tau. P and n define locally an effective polytropic index. Gamma ranges between 5/3 and 1, depending on the value of tau and on geocentric distance. The qualitative differences between the recent empirical determinations of the polytropic index by Baumjohann and Paschmann and Huang et al. may be accounted for in part by this simple model.},

  doi          = {},

  url          = {https://www.osti.gov/biblio/6046665},
  journal      = {},
number       = ,

  volume       = ,

  place        = {United States},

  year         = {Wed Aug 15 00:00:00 EDT 1990},

  month        = {Wed Aug 15 00:00:00 EDT 1990}

}

Copy to clipboard

Technical Report:

Other availability

Please see Document Availability for additional information on obtaining the full-text document. Library patrons may search WorldCat to identify libraries that may hold this item. Keep in mind that many technical reports are not cataloged in WorldCat.

Save / Share:

Export Metadata

Save to My Library

Similar records in OSTI.GOV collections:

The variation of the plasma sheet polytropic index along the midnight meridian in a finite width magnetotail

Journal Article Spence, H; Kivelson, M - Geophysical Research Letters (American Geophysical Union); (USA)

The authors have obtained the polytropic index as a function of distance along the midnight meridian in the terrestrial magnetotail. As their purpose is to establish the effects of the finite width of the magnetotail, they use a simple theoretical model of plasma sheet convection, i.e., 2-dimensional (2D) field structure and adiabatic inward convection of a uniform distant tail source. Particle orbits are treated independently for portions of the phase space distribution on shells of constant energy. On the midnight meridian, the moments of the distribution are parameterized by {tau}, the ratio of half the crosstail potential energy to themore »« less
https://doi.org/10.1029/GL017i005p00591
Magnetospheric plasma pressures in the midnight meridian: Observations from 2. 5 to 35 R sub E

Journal Article Spence, H; Kivelson, M; Walker, R; ... - Journal of Geophysical Research; (USA)

Plasma pressure data from the ISEE 2 fast plasma experiment (FPE) were statistically analyzed to determine the plasma sheet pressure versus distance in the midnight local time sector of the near-earth (12-35 R{sub E}) magnetotail plasma sheet. The observed plasma pressure, assumed isotropic, was mapped along model magnetic field flux tubes (obtained from the Tsyganenko and Usmanov (1982) model) to the magnetic equator, sorted according to magnetic activity, and binned according to the mapped equatorial location. In regions (L {approx gt} 12 R{sub E}) where the bulk of the plasma pressure was contributed by particles in the energy range ofmore »« less
https://doi.org/10.1029/JA094iA05p05264
Contributions of the low-latitude boundary layer to the finite width magnetotail convection model

Technical Report Spence, H; Kivelson, M

Convection of plasma within the terrestrial nightside plasma sheet contributes to the structure and, possibly, the dynamical evolution of the magnetotail. In order to characterize the steady state convection process, the authors have extended the finite tail width model of magnetotail plasma sheet convection. The model assumes uniform plasma sources and accounts for both the duskward gradient/curvature drift and the earthward E [times] B drift of ions in a two-dimensional magnetic geometry. During periods of slow convection (i.e., when the cross-tail electric potential energy is small relative to the source plasma's thermal energy), there is a significant net duskward displacementmore »« less
Contributions of the low-latitude boundary layer to the finite width magnetotail convection model

Journal Article Spence, H; Kivelson, M - Journal of Geophysical Research

Convection of plasma within the terrestrial nightside plasma sheet contributes to the structure and, possibly, the dynamical evolution of the magnetotail. In order to characterize the steady state convection process, the authors have extended the finite tail width model of magnetotail plasma sheet convection. The model assumes uniform plasma sources and accounts for both the duskward gradient/curvature drift and the earthward E x B drift of ions in a two-dimensional magnetic geometry. During periods of slow convection (i.e., when the cross-tail electric potential energy is small relative to the source plasma`s thermal energy), there is a significant net duskward displacementmore »« less
https://doi.org/10.1029/93JA01531
Consequences of magnetotail ion dynamics

Journal Article Ashour-Abdalla, M; Peroomian, V; Zelenyi, L - Journal of Geophysical Research

The trajectories of a large ensemble of particles are calculated in a modified Tsyganenko magnetic field with a uniform cross-tail electric field. The model magnetotail can be divided into several distinct dynamical regimes of ion motion. Near Earth, where the field lines are dipolar the adiabatic formalism is adequate. In the mid-tail and distant tail, guiding-center theory breaks down and must be replaced by a quasi-adiabatic formalism. There is an important transition region between the adiabatic and quasi-adiabatic regions where ion trajectories become more complicated and no simple analytical description holds. This wall region is characterized by rapid ion accelerationmore »« less
https://doi.org/10.1029/94JA00141

Similar Records