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EP: Extraterrestrische Physik

EP 2: Extraterrestrik-Poster

EP 2.1: Poster

Montag, 18. März 2002, 13:30–14:30, Galerie 1

ANALYTICAL INVESTIGATION AND NUMERICAL SIMULATIONS OF INSTABILITIES OF THIN CURRENT SHEETS — •Ilya Silin¹, Jörg Büchner¹, and Lev Zelenyi² — ¹Max-Planck Institut für Aeronomie, Katlenburg-Lindau — ²Space Research Institute, Moscow

We derived an analytical solution of the linear dispersion relation for the instabilities of thin Harris current sheets. In our analytical investigation we focused at symmetric long-wavelength instabilities. This allowed us to reduce the problem to a system of algebraic equations and to determine parametric dependence of the instability on such parameters as electrostatic potential perturbations, current sheet thickness, wave propagation angle and particle mass ratio. The solution revealed that the electrostatic perturbations stabilize obliquely propagating modes for realistic particle mass ratios. In order to verify our analytical results, we also carried out numerical simulations of the current sheet stability, which showed, that the wavelength of the fastest-growing mode shifts to the short-wavelength region. Thus, it appears that current-driven instabilities of current sheets may remain unstable for realistic mass ratios only in the short-wavelength regime.