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EP: Fachverband Extraterrestrische Physik

EP 3: Poster

EP 3.24: Poster

Montag, 15. März 2010, 17:45–19:00, AKM Foyer

Almost monoenergetic ions during IP shock passages: STEREO/SEPT observations — Andreas Klassen, Raul Gomez-Herrero, Reinhold Müller-Mellin, and •Bernd Heber — IEAP, Universität Kiel, Deutschland

We present observations of ion events in the energy range of 100-1000 keV during the times of interplanetary (IP) forward shock passages associated with Corotating Interaction Regions (CIR). The detected energy spectra contain strong peaks with relative widths at half maximum (FWHM) of 0.3-0.6 and their energy maxima lie around 150 and 230 keV. The duration of the events varies from some minutes up to half an hour. These events were detected when STEREO-A or STEREO-B were relatively far away from the Earth at distances from 0.27 up to 1.0 AU.

In the past similar spectral peaks, so-called Almost Monoenergetic Ion (AMI) events, were detected during upstream events close to the Earth's bow-shock using observations on Interball-1 and STEREO A & B. We discuss the origin of these events and present indications that the narrow spectral peaks may be caused by quasi-monoenergetic beams of protons accelerated at the IP shock.