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Ion and electron accelerations by large‐scale shear Alfvén waves via cross‐field instabilities
Author(s) -
Khazanov Igor,
Singh Nagendra
Publication year - 2007
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 - 10.1029/2007gl031444
Subject(s) - physics , electron , electric field , ion , particle acceleration , magnetic field , instability , computational physics , atomic physics , polarization (electrochemistry) , mechanics , quantum mechanics , chemistry
Using two‐dimensional particle‐in‐cell simulations we study the linear and nonlinear effects of a large‐scale shear Alfvén wave (LS‐SAW) propagating parallel to the ambient magnetic field B o . We demonstrate that ion polarization drift in the propagating SAW drives cross‐field instability (CFI) by ion‐electron coupling and produces electrostatic (ES) waves, which accelerate electrons parallel and ions perpendicular to B o . Even though the large‐scale SAW has no parallel electric field E ∥ , the E ∥ of the ES wave fields embedded in LS‐SAW provide a novel acceleration mechanism for the electrons moving with the group velocity of the LS‐SAW. Examining data from satellite observations, we suggest that the mechanism of CFI for plasma acceleration/heating powered by LS‐SAWs is distinctly possible on auroral field lines.