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N.V. Nitta (LMSAL), H.S. Hudson (UCB/SPRC), J.S. Newmark (NRL)
Observations from Yohkoh SXT have identified different patterns of coronal dimming around the times of coronal mass ejections (CMEs), but the mapping between the dimming and the CME is still not well understood. There is always a possibility that the observed dimming may simply reflect cooling rather than mass depletion due to ejection. Empirically, dimming seen in SOHO EIT images appears to be more intimately associated with CMEs, although EIT images with narrower sensitivities should be more susceptible to changes in temperature. In this work, we compare SXT and EIT images systematically for various patterns of dimming, in order to understand possibly different origins of CMEs. We use new calibrations for both sets of images that allow us to more accurately estimate the changes of temperature/density that account for the observed level of dimming. We concentrate on events with good coverage to study the time dependence of coronal dimming at different temperatures.
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Bulletin of the American Astronomical Society, 34
© 2002. The American Astronomical Soceity.