Researchers Samuel W. Jones, Colin P. McNally, and Meritt Reynolds, affiliated with Los Alamos National Laboratory, have developed a new computational method aimed at improving the simulation of pulsed-power magneto-inertial fusion devices. Their work, published in the Journal of Computational Physics, focuses on solving the equations of compressible resistive magnetohydrodynamics (MHD) on a Cartesian mesh with an embedded boundary of arbitrary shape.
The researchers’ method is designed to address the challenges posed by the complex geometries often encountered in fusion energy research. By using a finite volume formulation and a Riemann solver to compute fluxes between grid cells, they can accurately model the behavior of plasma and magnetic fields within these devices. The method also employs a face-centered constrained transport formulation of the induction equation to maintain the divergence-free nature of the magnetic field, which is crucial for accurate MHD simulations.
One of the key innovations in this research is the use of a ghost-fluid approach to model a moving interface between two materials with different properties. This allows the method to simulate the dynamic interactions between different regions of a fusion device, such as the plasma and the surrounding material. The researchers demonstrate the capabilities of their method through preliminary results, including simulations of shock-wave-driven and magnetically-driven dynamical compressions of magnetohydrostatic equilibria.
The method has been thoroughly verified and shown to converge at second order in the absence of discontinuities, and at first order with a discontinuity in material properties. This high level of accuracy is essential for reliable predictions in fusion energy research. The researchers hope that their method will contribute to the development of more efficient and effective pulsed-power magneto-inertial fusion devices, bringing us closer to the goal of practical fusion energy.
Source: Jones, S. W., McNally, C. P., & Reynolds, M. (2023). A constrained-transport embedded boundary method for compressible resistive magnetohydrodynamics. Journal of Computational Physics, 111779.
This article is based on research available at arXiv.