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A new stationary analytical model of the heliospheric current sheet and the plasma sheet
Author(s) -
Kislov Roman A.,
Khabarova Olga V.,
Malova Helmi V.
Publication year - 2015
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
eISSN - 2169-9402
pISSN - 2169-9380
DOI - 10.1002/2015ja021294
Subject(s) - heliospheric current sheet , physics , solar wind , current sheet , interplanetary magnetic field , plasma sheet , plasma , magnetohydrodynamics , corona (planetary geology) , angular momentum , photosphere , magnetic field , computational physics , mechanics , astrophysics , classical mechanics , magnetosphere , astrobiology , venus , quantum mechanics
We develop a single‐fluid 2‐D analytical model of the axially symmetric thin heliospheric current sheet (HCS) embedded into the heliospheric plasma sheet (HPS). A HCS‐HPS system has a shape of a relatively thin plasma disk limited by separatrices that also represent current sheets, which is in agreement with Ulysses observations in the aphelion, when it crossed the HCS perpendicular to its plane. Our model employs a differential rotation of the solar photosphere that leads to unipolar induction in the corona. Three components of the interplanetary magnetic field (IMF), the solar wind speed, and the thermal pressure are taken into account. Solar corona conditions and a HCS‐HPS system state are tied by boundary conditions and the “frozen‐in” equation. The model allows finding spatial distributions of the magnetic field, the speed within the HPS, and electric currents within the HCS. An angular plasma speed is low within the HPS due to the angular momentum conservation (there is no significant corotation with the Sun), which is consistent with observations. We found that the HPS thickness L decreases with distance r , becoming a constant far from the Sun ( L ~2.5 solar radii ( R 0 ) at 1 AU). Above the separatrices and at large heliocentric distances, the solar wind behavior obeys Parker's model, but the magnetic field spiral form may be different from Parker's one inside the HPS. At r ≤ 245 R 0 , the IMF spiral may undergo a turn simultaneously with a change of the poloidal current direction (from sunward to antisunward).