No. 149,
The Alfven Speed above a Sunspot, and Gamma-rays
by H. Hudson and L. Fletcher.
Flare effects in sunspot umbrae...
http://sprg.ssl.berkeley.edu/~tohban/wiki/index.php/The_Alfven_Speed_above_a_Sunspot,_and_Gamma-rays
Older Nuggets are available at
http://sprg.ssl.berkeley.edu/~tohban/wiki/index.php/RHESSI_Science_Nuggets
(the new series), and at
http://sprg.ssl.berkeley.edu/~tohban/nuggets/
(the original series).
We publish these at roughly two-week intervals and welcome
contributions, which should be at least loosely related to RHESSI
science.