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| Titel |
Foreshocks ahead of interplanetary shocks observed by STEREO. |
| VerfasserIn |
Xochitl Blanco-Cano, Primoz Kajdic, Christopher T. Russell, Lan K. Jian, Janet G. Luhmann, Ernesto Aguilar-Rodriguez |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250107981
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| Publikation (Nr.) |
 EGU/EGU2015-7709.pdf |
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| Zusammenfassung |
| Interplanetary (IP) shocks can be driven in the solar wind by coronal mass ejections
and stream interactions. Shocks can perturb large extensions of the heliosphere.
In this work we study shocks observed by STEREO during the years 2007-2014.
During this period IP shocks had Mach numbers MMs ~1.1-4, and the majority were
quasi-perpendicular (θBn > 45Ë ) at the time of spacecraft crossing. We analyze wave
properties in the foreshock regions that preced the shocks. We find that when the
shock is very oblique with angle θBn > 60°a short region of the upstream side
is permeated by whistler waves with frequency f~ 1 Hz. For some less oblique
shocks (60°> θBn > 45Ë ), whistlers appear close to the shocks, and wave
spectra show two extra peaks, with frequencies f~10-1, 10-2 Hz. The origin of
these two wave components may be explained in terms of whistlers propagating
from adjacent regions of the shock, or by local instabilities. When the shock is
quasi-parallel (θBn |
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