HR: 08:40h
AN: SH31B-03    [Abstracts]
TI: Energy Cascades in the Heliospheric Turbulence
AU: * Shaikh, D
EM: dastgeer@ucr.edu
AF: Institute of Geophysics and Planetary Physics, University of California, 900 University Avenue, Pierce Bldg. Room#2112, Riverside, CA 92521, United States
AB: A local turbulence model, to study energy cascades in the interstellar medium (ISM), is developed based on self-consistent two-dimensional fluid simulations. The model describes a partially ionized magnetofluid interstellar medium (ISM) that couples a neutral hydrogen fluid with a plasma primarily through charge exchange interactions, and assumes that the ISM turbulent correlation scales are much bigger than the shock characteristic length-scales. Charge exchange interactions occur ubiquitously in warm ISM plasmas in a subtle nonlinear manner whose strength depends largely on the relative speed between the plasma and the neutral fluid. Unlike small length-scale linear collisional dissipation in the fluid, charge exchange processes can be effective on a variety of ISM length-scales depending upon the neutral and plasma densities, charge exchange cross section and the characteristic length scales. We find, from scaling arguments and nonlinear coupled fluid simulations, that charge exchange interactions modify spectral transfer associated with largescale energy containing eddies. Consequently, the warm ISM turbulent cascade rates lead to a rapid spectral transfer amongst inertial range modes. Turbulent spectra associated with the neutral and plasma ISM fluids are therefore steeper than those predicted by Kolmogorov's phenomenology.
DE: 4400 NONLINEAR GEOPHYSICS (3200, 6944, 7839)
DE: 4490 Turbulence (3379, 4568, 7863)
DE: 7839 Nonlinear phenomena (4400, 6944)
DE: 7859 Transport processes
DE: 7863 Turbulence (4490)
SC: SPA-Solar and Heliospheric Physics [SH]
MN: 2007 Fall Meeting