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Titel |
CME-related particle acceleration regions during a simple eruptive event near solar minimum |
VerfasserIn |
Carolina Salas Matamoros, Karl-Ludwig Klein, Alexis Rouillard |
Konferenz |
EGU General Assembly 2016
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Medientyp |
Artikel
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Sprache |
en
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Digitales Dokument |
PDF |
Erschienen |
In: GRA - Volume 18 (2016) |
Datensatznummer |
250126371
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Publikation (Nr.) |
EGU/EGU2016-6080.pdf |
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Zusammenfassung |
An intriguing feature of many solar energetic particle (SEP) events is the detection of
particles over a very extended range of longitudes in the Heliosphere. This may be due to
peculiarities of the magnetic field in the corona, to a broad accelerator, to cross-field transport
of the particles, or to a combination of these processes.
The eruptive flare of the 26th of April 2008 offered an opportunity to study relevant
processes under particularly favorable conditions, since it occurred in a very quiet solar and
interplanetary environment. This allowed us to investigate the physical link between a single
well-identified Coronal Mass Ejection (CME), electron acceleration as traced by radio
emission, and the production of SEPs.
We conduct a detailed analysis combining radio observations (Nançay Radioheliograph
and Decameter Array, Wind/WAVES spectrograph) with remote-sensing observations of the
corona in extreme ultraviolet (EUV) and white light as well as in-situ measurements of
energetic particles near 1AU (SoHO and STEREO spacecraft). By combining images taken
from multiple vantage points we were able to derive the time-dependent evolution of the 3-D
pressure front developing around the erupting CME.
Magnetic reconnection in the post-CME current sheet accelerated electrons that remained
confined in closed magnetic fields in the corona, while the acceleration of escaping particles
can be attributed to the pressure front generated ahead of the expanding CME. The CME
accelerated electrons remotely from the parent active region, due to the interaction of its
laterally expanding flank, traced by an EUV wave, with the ambient corona. SEPs detected at
one STEREO spacecraft and SoHO were accelerated later, when the frontal shock of the
CME intercepted the spacecraft-connected interplanetary magnetic field line. The injection
regions into the Heliosphere inferred from the radio and SEP observations are separated in
longitude by about 140∘.
The observations for this event show that it is misleading to interpret multi-spacecraft
SEP measurements in terms of one acceleration region in the corona. The different
acceleration regions are linked to different vantage points in the interplanetary space. |
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