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Grad‐Shafranov Reconstruction of Earth's Magnetopause With Temperature Anisotropy
Author(s) -
Chen G.W.,
Hau L.N.
Publication year - 2018
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
eISSN - 2169-9402
pISSN - 2169-9380
DOI - 10.1029/2018ja025842
Subject(s) - magnetopause , physics , adiabatic process , magnetohydrodynamic drive , anisotropy , computational physics , isotropy , magnetohydrodynamics , magnetic field , field (mathematics) , polytropic process , mechanics , geophysics , magnetosphere , thermodynamics , quantum mechanics , mathematics , pure mathematics
The Grad‐Shafranov (GS) reconstruction may recover the steady two‐dimensional magnetohydrodynamic equilibrium structure from single spacecraft data. In this study we report first results on magnetopause structure from a newly developed GS solver that includes the effects of temperature anisotropy and field‐aligned flow. Double‐polytropic laws are used as energy closure to describe various thermodynamic states for anisotropic plasmas including double‐adiabatic and isothermal conditions as special cases. The new GS solver is benchmarked and applied to a Time History of Events and Macroscale Interactions during Substorms magnetopause crossing event with field‐aligned flow and p ⊥ > p ∥ , where p ⊥ and p ∥ are the pressure components perpendicular and parallel to the local magnetic field, respectively. The recovered magnetic field maps for various thermodynamic conditions show qualitatively similar features with magnetic islands imbedded within the magnetopause current. The mirror‐type anisotropy with p ⊥ > p ∥ may lead to relatively inflated magnetic islands as compared to the isotropic case, consistent with earlier theoretical prediction.