TRACE and RHESSI observations of white-light flares
H. Hudson (UCB), J. Wolfson (LMSAL), and T. Metcalf (CORA)
The TRACE instrument includes a "white light" (WL) imaging capability
with novel characteristics. Flares down to GOES class C1.3 with WL
emission have been detected, and this paper provides an introductory
overview of these data. These observations have 0.5" pixel size
and use the full broad-band response of the CCD sensor. The spectral
response of the TRACE white-light passband extends into the UV, so
these data capture, for the first time in images, the main radiative
energy of a flare. This initial survey is based on a sample of
flares observed at high time resolution for which RHESSI had
complete data coverage, a total of 11 events up to the end of 2004.
We characterize these events in terms of source morphology and
contrast against the photosphere. We confirm the strong association
of the TRACE white-light emissions - which in clude UV as well as
visual wavelengths - with hard X-ray sources observed by RHESSI.
The images show fine structure at the TRACE resolution limit, and
often show this fine structure to be extended over large areas
rather than just in simple footpoint sources. The white-light
emission shows strong intermittency both in space and in time and
commonly has features unresolved at the TRACE resolution.
Correspondence
Hudson, Hugh (hhudson@ssl.berkeley.edu), UC Berkeley
presentation
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