Efficient kinetic Lattice Boltzmann simulation of three-dimensional magneto-hydrodynamic turbulence
Résumé
The opportunity of using a kinetic Lattice Boltzmann (LB) approach for the numerical simulation of three-dimensional magneto-hydrodynamic (MHD) turbulence is examined. A significant advantage of dealing with a kinetic representation of the plasma (even in simulating the MHD scales) is that the derivatives of the magnetic field are directly encompassed in the solution, thus allowing for an intrinsically accurate description of the small-scale current density structures. A novel LB framework is proposed here to address the three-dimensional Orszag-Tang vortex problem at increasing Reynolds numbers. Our analysis shows that both small-scale dynamics and spectral properties of LB runs are compatible with the outcome of analogous pseudo-spectral simulations (Mininni et al. 2006) generated with a well-established pseudo-spectral code (Mininni et al. 2011; Pou-quet et al. 2019). This study shows how phenomenology of MHD turbulence is suitably captured by our LB simulations, which reproduced it with accuracy and computational efficiency. The newly developed algorithm couples two LB schemes for fluid dynamics including the Lorentz force and the magnetic induction equation respectively. The fluid incompressibility is achieved in the low-Mach-number limit, whereas the divergence-free condition for the magnetic field is preserved within machine precision. It is also emphasized how such novel scheme is amenable to a high level of parallelism and can exploit the computational power of many-core accelerators such as Graphic Processing Units (GPUs) thus leading to very advantageous turnaround times. This is supported by a preliminary benchmark that shows the high scalability of our model implementation.
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