NUMERICAL SIMULATIONS OF LARGE-SCALE SOLAR-WIND FLUCTUATIONS OBSERVED BY ULYSSES AT HIGH HELIOGRAPHIC LATITUDES

An analysis of Ulysses plasma and magnetic field data from the high southern latitude pass revealed that at large spatial scales corresponding to wave frequencies below 10(-5) Hz in the spacecraft frame, there is a transition from highly Alfvenic turbulence in all three spatial components of the fields to fluctuations which are Alfvenic only in field components transverse to the radial direction with uncorrelated radial magnetic and velocity fields. We find that the general properties of the turbulence can be simulated using a spectral method solution of the magnetohydrodynamic (MHD) equations only when certain types of initial conditions are employed. These simulations place constraints on conditions in the solar atmosphere that can generate the observed fluctuations.