Orthonormal Divergence-Free Wavelet Analysis of Energy Transfer in Hall MHD Turbulence

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We studied the basic features of energy transfer in fully developed, freely decaying, isotropic, and homogeneous turbulence in magnetohydrodynamic (MHD) and Hall MHD (HMHD) media using orthonormal divergence-free wavelet analysis. The analysis supports the idea that energy transfer occurs locally; i.e., intense energy transfer occurs between modes that have very close spatial scales. The wavelet counterpart of triad interaction analysis in Fourier analysis shows that local interaction, i.e., combinations of three wavelet modes that have very close spatial scales, dominates the energy exchange between the velocity and magnetic fields. Energy transfer due to the Hall effect has opposite tendencies at larger and smaller scales, which is consistent with the results of Mininni et al. [P.D. Mininni et al., J. Plasma Phys. 73, 377 (2007)]. At larger scales, it causes a moderate inverse cascade. In contrast, it causes an intense forward cascade at smaller scales.