FILAMENTATION INSTABILITY OF NONLINEAR ALFVEN WAVES IN WEAKLY IONIZEDPLASMAS

We investigate an instability that leads to the filamentation of large -amplitude Alfven waves propagating along a homogeneous magnetic held in weakly ionized plasmas by using a neutral MI-ID simulation code. Th e dispersion relation of small-amplitude Alfven waves is confirmed by a one-dimensional simulation code. The linear instability leading to t he filamentation is investigated by imposing small density perturbatio ns across a magnetic field. We demonstrate the results of the nonlinea r stage of the above filamentation instability with a two-dimensional simulation showing the occurrence of localized plasma heating during r epeated coalescence and fission of the filaments. We discuss the impli cation of these results for plasma-heating processes observed in the p hotosphere of the Sun.