Freiburg 2008 – wissenschaftliches Programm
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EP: Fachverband Extraterrestrische Physik
EP 4: The Sun and Heliosphere - Poster Session
EP 4.2: Poster
Montag, 3. März 2008, 17:30–19:00, Vorraum KGI-Aula
Coronal loop model including ion kinetics — •Sofiane Bourouaine1, Christian Vocks2, and Eckart Marsch1 — 1Max-Planck-Institut für Sonnensystemforschung, 37191 Katlenburg-Lindau, Germany — 2Astrophysikalisches Institut Potsdam, 14482 Potsdam, Germany
We present a kinetic coronal loop model including collisions and wave-particle interactions to study the mechanisms of loop heating. The model is based on a quasilinear treatment of the Vlasov equation for the reduced velocity distribution functions of the protons, which are the only ions considered in the loop plasma. We assume that linear Alfvèn waves penetrate the loop from its footpoints and heat the protons via wave-particle interactions and wave absorption. Through Coulomb collisions between protons and electrons some thermal energy can be transferred to the electrons. Furthermore, it is shown that in case of a nearly homogeneous flux-tube cross section, an almost flat temperature profile occurs along the major part of the loop with an enhanced plasma density. These plasma parameter profiles are consistent with those of loops having temperatures between 1 and 1.5 MK as observed in EUV emission. However, if the magnetic field lines are more strongly diverging from the footpoints to the loop apex, the proton heating is found to be more uniform, resulting in a higher temperature and lower density along the loop. These profiles are similar to those observed in X-ray loops.