NONLINEAR EVOLUTION OF ALFVENIC WAVE-PACKETS

Alfven waves are a ubiquitous feature of the solar wind. One approach to studying the evolution of such waves has been to study exact soluti ons to approximate evolution equations. Here we compare soliton soluti ons of the Derivative Nonlinear Schrodinger evolution equation (DNLS) to solutions of the compressible MHD equations. We find that the solit on solutions of the DNLS equation are not stable solutions of Hall-MHD - they evolve and dissipate with time..Although such solitons may ser ve as approximate initial conditions to the Hall-MHD equations, they a re not stationary solutions. This may account for the absence of solit on-like wave forms in the free-flowing solar wind.