Enabling Breakthrough Kinetic Simulations of the Magnetosphere via Petascale Computing
Homayoun Karimabadi, University of California, San Diego
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Bart Semeraro, Frank Tsung, Homayoun Karimabadi, Mahidhar Tatineni, William Daughton, Hoanh Vu, Ryan Mokos, Vadim Roytershteyn, Utkarsh Ayachit, Berk Geveci, Kai Germaschewski, David DeMarle, Yi-Hsin Liu, Ari LeThe ultimate goal in space physics is to understand how solar wind transfers its mass, momentum, and energy to the magnetosphere. The understanding of this interaction is of great practical relevance. The Earth’s magnetic field, for the most part, shields us from the direct effects of the solar wind. However, this shielding is not perfect and the term “space weather” has been coined to describe the conditions in space that affect the Earth and its technological systems, including Global Positioning System satellites, geosynchronous communication and weather satellites, large-scale power distribution grids, and navigation and communications systems through the ionosphere.
A major reason for the complexity in solar wind-magnetosphere interaction is the dominance of ion kinetic effects, which occur on small ion scales but affect the large-scale dynamics of the magnetosphere. Spacecraft observations have established the fact that most critical plasma processes regulating mass and energy transfer in the magnetosphere take place at relatively thin boundaries/discontinuities between major regions of geospace where ions control the physics. Regions such as low latitude boundary layer and plasma sheet consist of many particle components that individually are often anything but thermalized Maxwellians. Furthermore, some of the regions such as the ion foreshock arise purely from ion kinetic effects and are absent in any fluid model of the magnetosphere.
Currently global simulations are predominantly based on single-fluid magnetohydrodynamics (MHD) but this project focuses on 3D global hybrid (fluid electrons, kinetic ions) particle-in-cell simulations of the Earth’s magnetosphere. These simulations will open new horizons for scientific understanding of the Sun-Earth system and will, for the first time, enable exploration of many long standing issues that are forever out of reach of MHD simulations.
