Two-dimensional Vlasov simulations of fast stochastic electron heating

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Abstract

Ionospheric heating experiments using high frequency ordinary (O) mode electromagnetic waves have shown the induced formation of magnetic field-aligned density striations in the ionospheric F-region. These striations are observed in association with lower-hybrid (LH) and upper-hybrid (UH) turbulence and significant electron heating, further enforcing the striations. High-energy electrons can result in the ionisation of neutrals and the formation of descending artificial ionospheric layers (DAILs). In the current context, we present the results of a two-dimensional (2D) numerical simulation conducted using a Vlasov-Maxwell code to study the mode-conversion of an O mode pump wave to trapped UH waves in a small-scale density striation. Subsequent multi-wave parametric decay is observed leading to UH and LH turbulence and the excitation of large amplitude electron Bernstein (EB) waves. Large-amplitude EB waves result in significant electron heating when the wave amplitude exceeds a threshold value for stochastic motion of the electrons. For typical experimental parameters, the simulated electron temperature is observed to rise from 1500 K to more than 5000 K in a fraction of a millisecond, much faster than the usual Ohmic heating due to collisions which occurs on second-scale. The stochastic electron heating could potentially be one of the mechanisms involved in the formation of DAILs.
Original languageEnglish
Pages (from-to)10638-10650
Number of pages13
JournalJournal of Geophysical Research: Space Physics
Volume122
Issue number10
Early online date16 Oct 2017
DOIs
Publication statusE-pub ahead of print - 16 Oct 2017

Keywords

  • Vlasov-Maxwell simulations
  • plasma-wave coupling
  • parametric 8 multi-wave excitation
  • field aligned striation
  • stochastic electron heating
  • DAILS
  • decending artificial iono- 14 spheric layers

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