Overview of HiFi -- implicit spectral element code framework for multi-fluid plasma applications

Abstract

An overview of the algorithm and a sampling of plasma applications of the implicit, adaptive high order finite (spectral) element modeling framework, HiFi, is presented. The distinguishing capabilities of the HiFi code include adaptive spectral element spatial representation with flexible geometry, highly parallelizable implicit time advance, and general flux-source form of the partial differential equations and boundary conditions that can be implemented in its framework. Early algorithm development and extensive verification studies of the two-dimensional version of the code, known as SEL, have been previously described [A.H. Glasser & X.Z. Tang, Comp. Phys. Comm., 164 (2004); V.S. Lukin, Ph.D. thesis, Princeton University (2008)]. Here, substantial algorithmic improvements and extensions are presented together with examples of recent two-and three-dimensional applications of the HiFi framework. These include a Cartesian two-dimensional incompressible magnetohydrodynamic simulation of low dissipation magnetic reconnection in a large system, a two-dimensional axisymmetric simulation of self-similar compression of a magnetic plasma confinement configuration, and a three-dimensional Hall MHD simulation of spheromak tilting and relaxation. Some planned efforts to further improve and expand the capabilities of the HiFi modeling framework are discussed.

Mancha3D Code: Multipurpose Advanced Nonideal MHD Code for High-Resolution Simulations in Astrophysics

“…The codes mentioned above use a single-fluid quasimagnetohydrodynamic formalism. Several newer codes have implemented a multifluid formalism for solar plasmas, where the different plasma components (such as neutral and charged components) are evolved separately as independent fluids interacting by collisions (Hillier, Takasao, and Nakamura, 2016;Lukin et al, 2016;Martínez-Gómez, Soler, and Terradas, 2017;Lani et al, 2017;Popescu Braileanu et al, 2019;Wójcik, Murawski, and Musielak, 2019;Martínez-Sykora et al, 2020;Popescu Braileanu and Keppens, 2022). This different class of codes still lack realistic physics, and will not be discussed here.…”

Magnetic reconnection in strongly magnetized regions of the low solar chromosphere

“…However, the ionization and recombination rates were assumed as fixed values rather than depended on temperature and density, so that the important role of recombination in chromospheric reconnection was not captured in that paper. Leake et al (2012Leake et al ( , 2013 used the reactive multi-fluid plasma-neutral module within the HiFi modeling framework (Lukin 2016) to study null-point magnetic reconnection in the solar chromosphere. A similar plasma-neutral module within a different code (Alvarez Laguna et al 2017) has been used to investigate the role of radiative cooling on chromospheric reconnection.…”