Vlasov Simulations Of Fast Stochastic Electron Heating Near The Upper Hybrid Layer

Ionospheric modification experiments conducted using high frequency, L-O mode electromagnetic waves have shown the induced formation of magnetic field-aligned density striations in the ionospheric F-region 1 , 2 . These striations are observed in association with lower and upper-hybrid turbulence and significant electron heating within the striation. The initial electron heating to temperatures of $u003e4000mathrm {K}$ is believed to be a prerequisite for the formation of suprathermal electron tails by strong Langmuir turbulence 3 . Such tails can result in the ionisation of neutrals and the formation of descending artificial ionospheric layers (DAILS) 4 . In the current context, we present the results of 1D and 2D numerical simulations conducted using a VlasovMaxwell code 5 to study the mode-conversion / coupling of an L-O mode pump wave to trapped upper hybrid waves within a density striation. Subsequent multi-wave parametric decay is observed leading to lower-hybrid turbulence and high amplitude electron Bernstein waves which (once exceeding the threshold amplitude for stochasticity) can result in significant electron heating. The electron temperatures observed of $u003e5000mathrm {K}$ in simulation are sufficient to initialise the formation of suprathermal electron tails as a precursor to generating descending artificial ionospheric layers (DAILS).