1. Implosions, RHESSI, and FASR H.S. Hudson Space Sciences Lab, UC Berkeley

2. 2 Contents Implosion concept Items stolen from the RHESSI book, chapter 2 A recent rarefaction wave? How does FASR help?

3. 3 Official implosion cartoon Hudson & Cliver 2001 Magnetoisobars

4. 4 GONG SOHO/MDI B dB Sudol & Harvey (2005), flare of 2003 Oct. 29, line-of-sight field differences

5. 5 Alfven-wave cartoon Fletcher & Hudson 2008

6. 6 Background information (flare movies)

7. 7 Implosive motion seen by RHESSI? Veronig et al. 2005

8. 8 More implosive motion? Ji et al. 2006

9. 9 Rarefaction wave? See Sam Freeland’s STEREO movie: http://www.lmsal.com/solarsoft/secchi/event_movies/gev_20080325_1836/scc _euvi_movie_pair_gev_20080325_1836_diff_j.html

10. 10 Conclusions There is (I think) a clear theoretical reason for flares to be implosions There’s plenty of circumstantial evidence for implosive motions in RHESSI observations, but can we be sure that we are properly following the velocity field? Sorry to have left out the RHESSI discoveries (Sui- Holman) but they did not cite my paper!