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Observation of lower hybrid drift instability in the diffusion region at a reconnecting magnetopause
Author(s) -
Bale S. D.,
Mozer F. S.,
Phan T.
Publication year - 2002
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 - 10.1029/2002gl016113
Subject(s) - magnetopause , instability , physics , current sheet , plasma sheet , geophysics , computational physics , lower hybrid oscillation , current density , electrical resistivity and conductivity , magnetosphere , plasma , drift current , diffusion , electric field , magnetohydrodynamics , mechanics , cyclotron , quantum mechanics , thermodynamics
Intense lower hybrid waves are observed in the Hall current region of a reconnecting current sheet at the earth's magnetopause. Large measured cross‐field drifts and density gradients are the likely sources of free energy through a lower hybrid drift instability (LHDI), which is stabilized near the neutral point where the plasma β is large. Harris neutral sheet and linear models are fitted to the data and inferred current density profiles are compared to the observed current density from particle measurements. We estimate the contribution of LHDI anomalous resistivity to the parallel electric field and show that it is more than 100 times smaller than the measured parallel field at the separator boundaries and essentially zero near the neutral point, leaving gradient electron pressure tensor and inertial terms or anomalous resistivity from higher frequency instabilities to support any parallel fields there and, hence, control the reconnection process.