The "transition corona" is the interface between the closed, strong magnetic fields of the inner corona, and the open fields of the outer corona. The key thing is that when we look at the XRT observations of active regions at the limb, the space above the ARs does not look at all the way one would expected it to. Based on white light observations, we should see larger and larger closed field loops, eventually becomeing cusp-shaped helmet streamers. But the X-ray regions don't look like that at all. An example of what we see is here: http://xrt.cfa.harvard.edu/xpow/20070130.html We propose a joint observation program between Hinode and CORONAS/ PHOTON TESIS to study the transition corona in detail at multiple wavelengths. |
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