Nonlinear Electron Cyclotron Oscillations And Cross-Field Transport In Exb Discharges

Cross-field anomalous transport is an important element of the operation and performance of E × B discharges. The anomalous electron current is driven by instabilities which may be excited in such plasmas due to presence of the strong E × B electron current. Using 1D particle-in-cell simulations we study the development of the the E × B drift cyclotron instability
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driven exclusively by the E × B flow, in absence of density and magnetic field gradients. In this case, the instability occurs due to the resonance between the ballistic $kv _{E} \times _{B}$ modes and electron cyclotron harmonics $m\omega _{ce}$. Initially, in the linear stage we observe the growth of the most unstable $m^{th}$ harmonic, consistent with the linear theory. At a later stage, the intense electron heating is observed due to phase-space mixing of the electron distribution function and the mode robustly reorganizes into the fundamental mode that propagates with the acoustic speed in the ion frame
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, with a sub-dominant spectrum of higher order cyclotron side-bands. A progressive inverse cascade to a larger scale structure (with a size larger than the the length scale of the fundamental mode) in the anomalous current is also observed in the non-linear stage.