Stuttgart 2012 – wissenschaftliches Programm
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EP: Fachverband Extraterrestrische Physik
EP 19: Sonne und Heliosphäre II
EP 19.4: Vortrag
Freitag, 16. März 2012, 11:30–11:45, V55.21
Coronal Mass Ejections detected during radio sounding observations with the MEX spacecraft — •Matthias Hahn1, Sami W. Asmar5, Micheal B. Bird4, Bernd Häusler2, Martin Pätzold1, Silvia Tellmann1, Bruce Tsurutani5, and G. Leonard Tyler3 — 1Rheinisches Institut für Umweltforschung, Abteilung Planetenforschung, Cologne, Germany — 2Institut für Raumfahrttechnik, Universität der Bundeswehr, Munich, Germany — 3Department of Electrical Engineering, Stanford, CA, USA — 4Argelander-Institut für Astronomie, Universität Bonn, Bonn, Germany — 5Jet Propulsion Laboratory, Caltech, Pasadena, CA, USA
The radio sounding technique is a powerful tool to investigate the structure of the solar corona when a radio transmitter is located near superior solar conjunction. Mars Express, in orbit about Mars, underwent solar conjunctions in 2004, 2006, 2008/09 and 2010/11. As part of the Radio Science Experiment MaRS radio-sounding measurements were recorded using the dual-frequency downlinks of the spacecraft during solar conjunctions. The transmitted radio signals propagated through the plasma of the solar corona. Changes in carrier frequency reveal the large-scale coronal structure as a function of distance from the Sun. MaRS observed several Coronal Mass Ejection (CME) events crossing the radio ray path. A detailed interpretation of these events is presented. A CME-model was adapted to the measured electron content in order to derive information on the electron density, plasma velocity and spatial structure of CME features. Results of various simulations are presented and compared with SOHO/LASCO data.