FINITE LARMOR RADIUS EFFECTS AND VELOCITY CORRELATIONS IN 2-DIMENSIONAL ELECTROSTATIC PLASMA TURBULENCE

Low-frequency electrostatic turbulence in low-beta plasmas is studied in two spatial dimensions by direct numerical simulations. In this lim it the guiding center velocity in the direction perpendicular to a hom ogeneous magnetic field is in a first approximation the EXB(0)/B-0(2) velocity. The electron Larmor radius can safely be set to zero for mos t relevant conditions, but the ion dynamics are noticeably influenced by their finite Larmor radius. In the present study we use a fluid mod el where these effects are included by a simple filtering operation. T he equilibrium spectra are investigated and compared with known analyt ical results. Particular attention is given to the finite Larmor radiu s effect for the turbulent diffusion of charged particles across magne tic field lines. The integral time scale and the micro time scale asso ciated with the velocity correlations for the turbulent flow are discu ssed with attention to their dependence on the finite Larmor radius co rrections. Finally, the numerical code is generalized to a hybrid mode l, which incorporates many ion species with different Larmor radii sim ultaneously present in the flow.