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Zakharov simulations of beam‐induced turbulence in the auroral ionosphere
Author(s) -
Akbari H.,
Guio P.,
Hirsch M. A.,
Semeter J. L.
Publication year - 2016
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
eISSN - 2169-9402
pISSN - 2169-9380
DOI - 10.1002/2016ja022605
Subject(s) - physics , langmuir turbulence , cascade , turbulence , energy cascade , electron , ionosphere , computational physics , plasma , beam (structure) , range (aeronautics) , incoherent scatter , langmuir probe , plasma oscillation , atomic physics , plasma diagnostics , geophysics , optics , mechanics , nuclear physics , chemistry , materials science , chromatography , composite material
Recent detections of strong incoherent scatter radar echoes from the auroral F region, which have been explained as the signature of naturally produced Langmuir turbulence, have motivated us to revisit the topic of beam‐generated Langmuir turbulence via simulation. Results from one‐dimensional Zakharov simulations are used to study the interaction of ionospheric electron beams with the background plasma at the F region peak. A broad range of beam parameters extending by more than 2 orders of magnitude in average energy and electron number density is considered. A range of wave interaction processes, from a single parametric decay, to a cascade of parametric decays, to formation of stationary density cavities in the condensate region, and to direct collapse at the initial stages of turbulence, is observed as we increase the input energy to the system. The effect of suprathermal electrons, produced by collisional interactions of auroral electrons with the neutral atmosphere, on the dynamics of Langmuir turbulence is also investigated. It is seen that the enhanced Landau damping introduced by the suprathermal electrons significantly weakens the turbulence and truncates the cascade of parametric decays.