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Solar Wind Ablation of Terrestrial Planet AtmospheresInternal plasma sources usually arise in planetary magnetospheres as a product of stellar ablation processes. With the ignition of a new star and the onset of its ultraviolet and stellar wind emissions, much of the volatiles in the stellar system undergo a phase transition from gas to plasma. Condensation and accretion into a disk is replaced by radiation and stellar wind ablation of volatile materials from the system- Planets or smaller bodies that harbor intrinsic magnetic fields develop an apparent shield against direct stellar wind impact, but UV radiation still ionizes their gas phases, and the resulting internal plasmas serve to conduct currents to and from the central body along reconnected magnetic field linkages. Photoionization and thermalization of electrons warms the ionospheric topside, enhancing Jeans' escape of super-thermal particles, with ambipolar diffusion and acceleration. Moreover, observations and simulations of auroral processes at Earth indicate that solar wind energy dissipation is concentrated by the geomagnetic field by a factor of 10-100, enhancing heavy species plasma and gas escape from gravity, and providing more current carrying capacity. Thus internal plasmas enable coupling with the plasma, neutral gas and by extension, the entire body. The stellar wind is locally loaded and slowed to develop the required power. The internal source plasma is accelerated and heated, inflating the magnetosphere as it seeks escape, and is ultimately blown away in the stellar wind. Bodies with little sensible atmosphere may still produce an exosphere of sputtered matter when exposed to direct solar wind impact. Bodies with a magnetosphere and internal sources of plasma interact more strongly with the stellar wind owing to the magnetic linkage between the two created by reconnection.
Document ID
20100024507
Acquisition Source
Goddard Space Flight Center
Document Type
Conference Paper
Authors
Moore, Thomas Earle
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Fok, Mei-Ching H.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Delcourt, Dominique C.
(Centre des Etudes Terrestraire et Planetaire Saint Maur des Fosses, France)
Date Acquired
August 24, 2013
Publication Date
September 1, 2009
Subject Category
Lunar And Planetary Science And Exploration
Meeting Information
Meeting: 2009 American Geophysical Union(AGU) Fall Meeting
Location: San Francisco, CA
Country: United States
Start Date: December 14, 2009
End Date: December 18, 2009
Sponsors: American Geophysical Union
Distribution Limits
Public
Copyright
Other

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