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Development of an Adaptive Non-Ideal MHD Simulation Tool for Multiple Space Science Applications
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| Our overarching goal is to develop a powerful, flexible, general use simulation tool applicable to a large variety of space science
problems. Over the last decade our group at the University of Michigan has developed a highly parallelized adaptive mesh refinement
scheme for solving the equations of ideal and resistive magnetohydrodynamics. The BATS-R-US code makes use of robust
high-resolution upwind finite-volume schemes and explicit and/or fully implicit time stepping to solve the time-dependent 3D MHD
equations in conservation form. A flexible block-based hierarchical tree data structure is used to facilitate automatic solution
adaptation on a logically Cartesian grid. With the support of a previous AISRP grant the proposing team has added the capability of
solving the Hall-MHD equations that enables a more realistic modeling of space science phenomena, such as magnetic reconnection.
Modern global simulation tools are now widely used to address a variety of space science problems. However, there are some extremely
important physics and performance limitations to our simulation capabilities. We plan to remove some of these limitations to extend
the physical validity and efficiency of space plasma simulation codes. Specifically: * We propose to develop a multi-fluid Hall MHD
code with anisotropic pressure. This ambitious goal will be approached through intermediate stages: multi-fluid MHD, single-fluid
MHD with anisotropic pressure, multi-fluid Hall MHD with isotropic pressure, and finally multi-fluid Hall MHD with anisotropic
pressure. * We propose to implement a new phenomenological resistivity model to efficiently model reconnection. * In order to mitigate
the computational cost we propose implement various subcycling algorithms into our code. This algorithmic improvement will benefit
many space physics applications that requires high resolution in a smallfraction of the computational domain. The BATS-R-US code is
already available to the space science community. The new algorithms will also be freely available to maximize the potential benefits. |
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