3D electrostatic gyrokinetic electron and fully kinetic ion simulation of lower-hybrid drift instability of Harris current sheet

摘要

The eigenmode stability properties of three-dimensional lower-hybrid-drift-instabilities (LHDI) in a Harris current sheet with a small but finite guide magnetic field have been systematically studied by employing the gyrokinetic electron and fully kinetic ion (GeFi) particle-in-cell (PIC) simulation model with a realistic ion-to-electron mass ratio m(i)/m(e). In contrast to the fully kinetic PIC simulation scheme, the fast electron cyclotron motion and plasma oscillations are systematically removed in the GeFi model, and hence one can employ the realistic m(i)/m(e). The GeFi simulations are bench-marked against and show excellent agreement with both the fully kinetic PIC simulation and the analytical eigenmode theory. Our studies indicate that, for small wavenumbers, k(y), along the current direction, the most unstable eigenmodes are peaked at the location where (k) over right arrow. (B) over right arrow = 0, consistent with previous analytical and simulation studies. Here, (B) over right arrow is the equilibrium magnetic field and (k) over right arrow is the wavevector perpendicular to the nonuniformity direction. As k(y) increases, however, the most unstable eigenmodes are found to be peaked at (k) over right arrow. (B) over right arrow not equal 0. In addition, the simulation results indicate that varying m(i)/m(e), the current sheet width, and the guide magnetic field can affect the stability of LHDI. Simulations with the varying mass ratio confirm the lower hybrid frequency and wave number scalings. Published by AIP Publishing.