Observations of Broadband Shear Alfvén-Wave Instabilities

Abstract

Shear Alfv\'en waves accompanied by a broad spectrum of magnetic fluctuations are observed to be destabilized by a weak field-aligned current, and resultant strong plasma diffusion is caused. The instability with frequencies much higher than an electron diamagnetic drift frequency is considered to be driven by a resistivity gradient and current in a finite-$\ensuremath{\beta}$ plasma.