Stuttgart 2012 – wissenschaftliches Programm

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EP: Fachverband Extraterrestrische Physik

EP 6: Sonne und Heliosphäre I

EP 6.2: Vortrag

Mittwoch, 14. März 2012, 14:15–14:30, V55.21

Ion velocity-space diffusion triggered by bulk velocity fluctuations in supersonic winds — •Hans Jörg Fahr and Mark Siewert — Argelander Institut für Astronomie, Universität Bonn, Auf dem Huegel 71, 53121 Bonn

We first study the kinetic reaction of ions when getting shuffled from one to the other side of consecutive bulk velocity jumps in a supersonic wind. The jumps are described by Rankine-Hugoniot MHD jump conditions. Using two kinetic invariants at the ion passage over such jumps gives us the ion velocity transformations from one to the other side of the jump structure. It is shown that each single jump passage can be described by a specific ion velocity space diffusion coefficient. As we can show this type of velocity space diffusion at larger solar distances is the dominant process energizing ions and will lead to observed ion energy spectra.