Simulations of Ideal MHD Turbulence in a Strongly Magnetized Medium
نویسندگان
چکیده
We analyze 3D numerical simulations of driven incompressible magnetohydrodynamic (MHD) turbulence in a periodic box threaded by a moderately strong external magnetic field. We find that the time scale for the energy cascade is consistent with the Goldreich-Sridhar model of strong MHD turbulence. Using higher order longitudinal structure functions we show that the turbulent motions in the plane perpendicular to the local magnetic field are similar to ordinary hydrodynamic turbulence while motions parallel to the field are very different. We present the structure tensor for the magnetic and velocity fields for Alfvenic and pseudo-Alfvenic turbulence. Finally, we suggest that the weak coupling between wave packets traveling in the direction of an external field may lead to a very slow decay of turbulent motions in molecular clouds, enhancing the ability of MHD turbulence to support such clouds against gravitational collapse. Subject headings: ISM:general-MHD-turbulence
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Simulations of MHD Turbulence in a Strongly Magnetized Medium
We analyze 3D numerical simulations of driven incompressible magnetohydrodynamic (MHD) turbulence in a periodic box threaded by a moderately strong external magnetic field. We sum over nonlinear interactions within Fourier wavebands and find that the time scale for the energy cascade is consistent with the Goldreich-Sridhar model of strong MHD turbulence. Using higher order longitudinal structu...
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