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Distribution of Region 1 and 2 currents in the quiet and substorm time plasma sheet from THEMIS observations
Author(s) -
Liu Jiang,
Angelopoulos V.,
Chu Xiangning,
McPherron R. L.
Publication year - 2016
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2016gl069475
Subject(s) - substorm , plasma sheet , geophysics , current sheet , physics , plasma , earth's magnetic field , geology , magnetosphere , magnetic field , magnetohydrodynamics , quantum mechanics
Although Earth's Region 1 and 2 currents are related to activities such as substorm initiation, their magnetospheric origin remains unclear. Utilizing the triangular configuration of THEMIS probes at 8–12 R E downtail, we seek the origin of nightside Region 1 and 2 currents. Our statistical study reveals that both kinds of currents exist in the plasma sheet during quiet and active times. Region 2 currents are deep inside the plasma sheet; Region 1 currents, which are farther away from the neutral sheet, extend to the plasma sheet boundary layer. At geomagnetic quiet times, the separation between the two currents is located ~2.5 R E from the neutral sheet. During substorms, the separation migrates toward (away from) the neutral sheet as the plasma sheet thins (thickens). These findings suggest that the plasma sheet is a source of Region 1 and 2 currents and its deformation is associated with redistribution of FAC sources in the magnetotail.