Thermodynamics of near earth plasma sheet and specific entropy parameter during substorm — A case study

Abstract

Heat transactions in the near earth plasma sheet at ISEE-2 site during the full course of a single substorm is analysed. The selected substorm was shown to exhibit an adiabatic growth phase with non-adiabatic expansion and recovery phases. During growth phase, the sheet acts as a mere passage for the flow of energy from solar wind into the earth's atmosphere,

supporting the driven model of substorms. The substorm analysed, in general, was a non-adiabatic e vent. The polytropic index η has proved to be unsuccessful in predicting the thermodynamic state of plasma sheet during substorm. Specific entropy parameter is suggested as a better tool for such predictions.