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On the origin of pressure and magnetic perturbations ahead of dipolarization fronts
Author(s) -
Zhou XuZhi,
Angelopoulos V.,
Liu Jiang,
Runov A.,
Li S.S.
Publication year - 2014
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
eISSN - 2169-9402
pISSN - 2169-9380
DOI - 10.1002/2013ja019394
Subject(s) - physics , plasma sheet , context (archaeology) , plasma , ion , magnetic field , computational physics , geophysics , atomic physics , astrophysics , magnetosphere , geology , nuclear physics , paleontology , quantum mechanics
Dipolarization fronts (DFs), earthward‐propagating structures in the Earth's magnetotail current sheet with sharp enhancements of the northward magnetic field B z , are typically preceded by minor decreases in B z . Other characteristic DF precursor signatures, including earthward flows and plasma density/pressure enhancements, have been explained in the context of ion acceleration and reflection at dipolarization fronts. In the same context here we simulate the spatial distribution of plasma pressure earthward of a convex DF. The resultant pressure distribution, which shows clear dawn‐dusk asymmetries with greater enhancements at the DF duskside, agrees with statistical observations. The simulation further reveals that the reflected ions can carry a secondary current earthward of the advancing DF, which explains the characteristic signature of the B z dip immediately ahead of the DF.