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On the Existence of MHD Critically Balanced Time Scales

POSTER

Abstract

The Sridhar Goldreich theory (SG95) of strong magnetohydrodynamic (MHD) turbulence in a perturbation of a static, mean magnetic field equilibrium anticipates that the nonlinear energy cascade time will evolve to balance the linear wave period.[1] Several arguments underpinning this conjecture of critical balance are evaluated in a pseudospectral Hall MHD simulation to determine whether the premises of SG95 could be relevant for extended MHD or kinetic models of turbulence. The nonlinearity parameter of SG95 is calculated for each mode to check whether the predicted increase to an asymptotic value of one has occurred. Various metrics of the energy cascade time are constructed from time profiles of energy spectra and spectrograms of the Hall MHD induction and momentum equation nonlinearities, which are in turn compared to the linear wave time.

[1] P. Goldreich and S. Sridhar. Toward a Theory of Interstellar Turbulence. II. Strong Alfvenic Turbulence, 438:763, Jan. 1995. 1.

Publication: A planned paper would discuss the findings of this computational work with theoretical explanation.

Presenters

  • Erik Hansen

    University of Texas at Austin

Authors

  • Erik Hansen

    University of Texas at Austin

  • A. Shukla

    The University of Texas at Austin, University of Texas

  • D.R. R Hatch

    Institute for Fusion Studies, University of Texas at Austin, UT-Austin, University of Texas

  • Prerana Sharma

    University of Texas at Austin

  • Justin Walker

    University of Wisconsin - Madison, University of Wisconsin, Madison

  • Philip J Morrison

    University of Texas at Austin