The Variation of the Plasma Sheet Polytropic Index Along the Midnight Meridian in a Finite Width Magnetotail

1990 ◽  
Author(s):  
H. E. Spence ◽  
M. G. Kivelson
Keyword(s):  
Plasma Sheet ◽  
Polytropic Index ◽  
Finite Width

scholarly journals Average plasma sheet polytropic index as observed by THEMIS

2017 ◽  
Vol 35 (2) ◽  
pp. 253-262 ◽  
Author(s):  
Dennis Frühauff ◽  
Johannes Z. D. Mieth ◽  
Karl-Heinz Glassmeier
Keyword(s):  
Plasma Sheet ◽  
Poor Correlation ◽  
Polytropic Index ◽  
Flux Vector ◽  
Broad Distribution ◽  
Active Time ◽  
Heat Flux Vector ◽  
Spacecraft Orbits ◽  
Spacecraft Data ◽  
Thermodynamic Processes

Abstract. Multi-spacecraft data from the years 2008 to 2015 of the THEMIS mission particularly in the near-Earth plasma sheet are used in order to empirically determine the polytropic index in the quiet and active time magnetotail. The results of a number of previous studies in the 1990s can be confirmed. An analysis of the total database, although showing poor correlation, results in an average polytropic index of γ = 1. 72. The active time plasma sheet is well correlated with an average γ = 1. 49. However, the data scattering suggests that the analysis of the data in total is not adequate. In order to reduce the timescales, individual spacecraft orbits are analyzed, giving a broad distribution of polytropic indices throughout the plasma sheet. The major part of the distribution falls in a range between γ = 0. 67 and γ = 2. Our results indicate a variety of thermodynamic processes in the magnetotail and an all-time presence of heat exchange of the plasma. A description of the plasma sheet using an equation of state with a single γ is probably inadequate. This necessitates the application of more sophisticated approaches, such as a parametrization of the heat flux vector in magnetohydrodynamic equations or a superposition of polytropic indices.

Case study of small scale polytropic index in the central plasma sheet

2015 ◽  
Vol 58 (11) ◽  
pp. 1993-2001 ◽  
Author(s):  
XueXia Pang ◽  
JinBin Cao ◽  
WenLong Liu ◽  
YuDuan Ma ◽  
HaoYu Lu ◽  
...  
Keyword(s):  
Plasma Sheet ◽  
Small Scale ◽  
Polytropic Index ◽  
Central Plasma ◽  
Central Plasma Sheet

scholarly journals Polytropic index of central plasma sheet ions based on MHD Bernoulli integral

2015 ◽  
Vol 120 (6) ◽  
pp. 4736-4747 ◽  
Author(s):  
Xuexia Pang ◽  
Jinbin Cao ◽  
Wenlong Liu ◽  
Yuduan Ma ◽  
Haoyu Lu ◽  
...  
Keyword(s):  
Plasma Sheet ◽  
Polytropic Index ◽  
Central Plasma ◽  
Central Plasma Sheet ◽  
Bernoulli Integral

Determination of the polytropic index in the plasma sheet

1989 ◽  
Vol 16 (4) ◽  
pp. 295-298 ◽  
Author(s):  
Wolfgang Baumjohann ◽  
Götz Paschmann
Keyword(s):  
Plasma Sheet ◽  
Polytropic Index
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