Theoretical aspects of kappa-distributed protons on the downstream side of the termination shock
Abstract
Kappa functions provide an attractive tool for describing astrophysical plasma systems that contain both thermal and nonthermal components. Mixed plasma systems of this type have been described theoretically and observed by various space missions, primarily in the form of a pick-up ion component emerging at higher energies, in addition to the thermal core making up the classical solar wind. We present recent results from a theoretical study investigating two concurring descriptions found in literature, demonstrating how two individual (thermal and nonthermal) components can be described as one joint kappa function after crossing the solar wind termination shock. As it turns out, the resulting single fluid description allows to derive a global all-sky joint kappa index that does not depend on details of the termination shock, but solely on the upstream thermal and nonthermal properties of the protons, including the pick-up ion abundance. Downstream properties of the resulting plasma are relevant for the plasma flow profile in the inner heliosheath; this is of high importance for a full theoretical understanding of outer heliospheric mission data, such as IBEX or Voyager.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2013
- Bibcode:
- 2013AGUFMSH33D..02S
- Keywords:
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- 7827 SPACE PLASMA PHYSICS Kinetic and MHD theory;
- 7811 SPACE PLASMA PHYSICS Discontinuities