SHINE: Physics of the Interplanetary Electric Potential and Modifications to Exosphere Models of the Solar Wind

Space Science Institute, Boulder CO

Investigators

Abstract

This SHINE Investigation focuses on the production of stellar winds and will provide information about the physics of double layers in natural plasmas. Stellar winds production is important for other astrophysical systems as well as understanding the solar wind that the Earth and other planetary systems are subject to. The Principal Investigator in acts as a SHINE-GEM Liaison where solar/solar-wind issues and geospace issues are communicated between two research communities and is active in the Los Alamos Space Weather Summer School where his research investigations have been used to create student research projects. This 3-year SHINE Investigation will make improvements to the physics of exosphere models of the solar wind and will determine how those improvements affect the properties of the solar wind and the exobase that drives it. The major advance will be to replace a static (in the Sun's reference frame) interplanetary potential with a potential made up of multiple weak double layers propagating in the solar wind plasma. The changed reaction of ions to moving potential structures (instead of a Sun-stationary potential structure) will result in: (1) changed terminal velocities for the protons and heavy ions as a function of the electron velocity distribution function at the exobase, (2) a related change in the total electrostatic potential needed to accelerate the solar wind, (3) heating, rather than cooling, of the ions as they are accelerated, (4) differences in the outward acceleration of protons and heavy ions. Using multiple double layers as the form of the potential in exosphere models for the interplanetary electric field will result in a more-physically correct model and should overcome several of the shortcomings that existing exosphere models have. As a fundamental part of this SHINE project, PIC plasma simulations will be run to discern critical properties of solar-wind double layers as inputs to the exosphere model.