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Collaborative VLA, SOHO and TRACE observations of nonthermal burst activity,
coronal mass ejections and transient EUV events
Robert F. Willson
(Tufts University)
VLA imaging observations at decimetric and metric wavelengths of the solar corona have been used to
investigate the nonthermal signatures of coronal mass ejections and transient
EUV events detected by SOHO and TRACE. VLA snapshot maps at 400 cm show
impulsive burst emission in the low corona beginning near the estimated
start time of a CME detected by LASCO's coronagraphs. The nonthermal burst
emission continued sporadically during the next several hours which included the
ejection of spatially separated CME components. The 400 cm bursts are located within an extended, curved source between two active regions detected by
EIT, suggesting that they were emitted within a large-scale loop whose
instability may have led to the triggering of the CME.Our 91 cm observations also
show the onset of a Type I noise storm following an EUV ejection event detected
at several wavelengths by EIT and TRACE and before the detection of the CME.
Type I burst emission is also detected a few minutes following small-scale EUV
transient events in the low corona, suggesting that these evolving EUV sources
may have played
a role in the production of nonthermal electrons that were eventually seen in the noise storm emission
at greater heights.
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