21 September 2017 - Mission Day: 7965 - DOY: 264

The figure is a composite image taken by three SOHO instruments at the time of the 21 April 2002 solar flare. The green image of the solar disk at the time of the flare was taken by EIT in light emitted by iron ions at about 2 million degrees Kelvin. The blue/white image of a coronal mass ejection associated with the flare was taken by LASCO in visible light. UVCS images of the region outlined in white were made in light from four ultraviolet emissions, each showing threads of ejected material at very different temperatures above the flare. The `images' are constructed from a time sequence of observations as the ejected material moved through a region located 0.63 solar radii above the flare site. From top to bottom the UVCS images are total intensities from the emission of iron ([Fe XVIII] 974 A), silicon (Si XII 499 A), oxygen (O VI 1032,1037 A), and neutral hydrogen (H I Lyman alpha 1216 A). These emissions tend to form in regions where the gas is at 6 million degrees K, 2 million degrees K, 300 thousand d egrees K, and 20 thousand degrees K, respectively. Spectroscopy can be used to probe the extreme conditions during a solar flare where non-thermal processes are thought to be involved in producing the observed emissions. This composite image was produced by Alexander Panasyuk (SAO).



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