Executive Summary of Research at Dartmouth
The Heliosphere & Astrosphere Research Group at Dartmouth College focuses on the computationally intense modeling of large-scale, low-density plasmas occurring in space physics and astrophysics settings. The sources of plasmas typically are stellar winds (mass outflows from stellar outer atmospheres) or inflow from the interstellar medium.
The particular research focus is the presence of neutral atoms (neutral gas) in these systems, making the plasmas only partially ionized. The sources of neutrals are the interstellar medium, but at times also other objects like stars or planets. Neutrals and plasmas interact weakly through charge exchange. The systems studied by us have sizes and parameters that preclude the equilibration of plasma and neutrals in the system even though they occupy the same space. A large research effort is dedicated to model the out-of-equilibrium neutrals correctly; this is accomplished with kinetic codes, multi-fluid codes, and particle trajectory codes.
Main projects and ongoing research interests
- Modeling of the outer heliosphere, with the help of global heliosphere models and test-particle trajectory codes modeling neutral helium and hydrogen, cross-referencing IBEX, Voyager, and HST data (currently funded by NASA).
- Modeling neutral evaporating exospheres of exoplanets in close-in orbits around their host star (currently funded by NSF).
- Simulating trajectories of interstellar atoms measured by the NASA/IBEX satellite, and NASA/IMAP, including time- and velocity dependent radiation pressure when necessary.
- Characterizing the time-dependent 3D solar wind, also out of the ecliptic, as realistic input for global heliosphere models.
- Computer simulations of stellar winds interacting with the interstellar medium (astrospheres)
- Computer simulations of stellar winds of binaries interacting with the interstellar medium
- Computer simulations of red giant stellar winds interacting with the interstellar medium
More details
- Heliosphere: The region where solar wind and the interstellar medium surrounding the Sun interact.
- Astrospheres: Interaction regions between stellar wind(s) and the partially ionized interstellar medium.
- Exospheres: Neutral material evaporated from exoplanets losing their atmosphere, and its interaction with the wind and photons from its host star.
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