Abstract Details
Abstracts
Author: Erik C Hansen
Requested Type: Poster
Submitted: 2024-04-15 15:30:02
Co-authors: Shukla, A., Hatch, D., Sharma, P., Walker, J., Morrison, P.J., Mahajan, S. M.
Contact Info:
University of Texas at Austin
2515 Speedway, C1600
Austin, TX 78705
United States
Abstract Text:
The Goldreich-Sridhar 1995 theory of MHD turbulence (SG95) originates in the study of interactions of shear Alfvén waves.[2] To study properties of wave turbulence in the Hall MHD system, we continue studying wave interactions by decomposing the velocity and magnetic field perturbations into eigenmodes of Hall MHD. The induction and velocity equations of Hall MHD are expanded in the basis of eigenmodes, in an extension of Mahajan 2021 [3], to obtain evolution equations for the wave amplitudes. These equations are analyzed to predict the dominant interactions driving modes at various regimes in wavenumber space. This decomposition is applied to results of a pseudospectral Hall MHD simulation to show how the total energy in each wave changes over the course of a simulation. To test whether the Hall MHD system also follows features of critical balance, the nonlinearity parameter of SG95 is calculated for each type of wave to determine whether an asymptotic value of one is achieved. The structure functions of Cho and Lazarian 2003 [1] and integrated energy spectra of Maron and Goldreich 2001 [4] are obtained to determine whether the waves are anisotropic or show a predicted scaling of -5/3.
This work was supported by United States Department of Energy Contract # DE-FG05-80ET-53088.
[1] J. Cho and A. Lazarian. Compressible magnetohydrodynamic turbulence: mode coupling, scaling relations, anisotropy, viscosity-damped regime and astrophysical implications. Monthly Notices of the Royal Astronomical Society, 345(1):325–339, 2003.
[2] P. Goldreich and S. Sridhar. Toward a Theory of Interstellar Turbulence. II. Strong Alfvénic Turbulence.
The Astrophysical Journal, 438:763, Jan. 1995.
[3] S. M. Mahajan. A new and alternative look at nonlinear Alfvénic states. Physics of Plasmas, 28(8):82303, 2021.
[4] J. Maron and P. Goldreich. Simulations of Incompressible Magnetohydrodynamic Turbulence. The Astrophysical Journal, 554(2):1175–1196, June 2001.
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