HR: 0800h
AN: SH11A-0251    [Abstracts]
TI: Compressible MHD and reduced MHD turbulence: direct numerical comparisons
AU: Dmitruk, P
EM: pablo@bartol.udel.edu
AF: Bartol - Dept. Physics and Astronomy, University of Delaware, 217 Sharp Lab University of Delaware, Newark, DE 19716 United States
AU: * Matthaeus, W H
EM: whm@udel.edu
AF: Bartol - Dept. Physics and Astronomy, University of Delaware, 217 Sharp Lab University of Delaware, Newark, DE 19716 United States
AU: Oughton, S
EM: seano@waikaton.ac.nz
AF: Dept. Mathematics, University of Waikato, Private Bag 3105, Hamilton, 3105 New Zealand
AB: Comparisons of low Mach number compressible three-dimensional magnetohydrodynamic (CMHD3D) turbulence in the presence of a strong mean magnetic field and reduced magnetohydrodynamics (RMHD) are performed using pseudospectral numerical simulations. Different initial conditions are chosen to study how close the RMHD solution remains to the full compressible MHD solution as both freely evolve in time. When the initial state is prepared to satisfy the conditions assumed in the derivation of RMHD, namely, a strong mean magnetic field, and plane-polarized fluctuations, varying weakly along the mean magnetic field, simulations show that RMHD and CMHD3D evolve almost indistinguishably from one another. When some of the conditions are relaxed the agreement worsens but RMHD remains fairly close to CMHD3D, especially when the mean magnetic field is large enough. Mean energy, square current, vorticity and energy spectrum from the two solutions are compared and point-to-point separation estimations are computed. The results give support to the use of RMHD as an approximation of compressible MHD with a mean magnetic field under certain but quite practical conditions, like those found in the solar corona and wind.
DE: 7509 Corona
DE: 7827 Kinetic and MHD theory
DE: 7863 Turbulence (4490)
SC: SPA-Solar and Heliospheric Physics [SH]
MN: Fall Meeting 2005