1. RHESSI Working Group 4 Program – Taos workshop
Friday am: 10:00 – 12:00
Introduction
WG 4 updates
Dennis
Hudson
Schmahl
Gallagher
Fletcher
Gopalswamy (WG3 invited)
– others?
Formulation of ‘science based’ questions.

2. 10:30-12:00 brainstorming science questions
and 1:30 – 3: and forming action plan
3.30 – 5.30 – joint with group 1 in big room

3. ‘Science-based’ versus ‘event-based’ questions
We need to generalise our studies of individual events.
- identify the underlying scientific motivations for our studies
- refine the questions being asked
- plan how to use a broader observational sample to
address questions.
- (hire some grad students)
For example: footpoints
What is special about HXR footpoint locations?
How well is the evaporation model holding up?
How are footpoint intensity/spectra/motions informing us about reconnection?

4. Ongoing projects HXR/EUV/Ha Footpoint structure + evolution
RHESSI/CDS joint studies
Plasma Diagnostics in looptop region
Apr 21 Rise phase energetics
Apr 21 ‘Mass chain’
Apr 21 origin of non-thermal particles
tie-in also with escaping particles

5. Broad event categories
Failed filament eruptions
Successful filament eruptions
Confined flares?
Footpoints (moving/stationary)
Moving coronal sources
Pre-flare coronal sources
Microflares

6. RHESSI Workshop III: WG 4 Summary
Presentations
Friday am:
Dennis (Phillips) – Progress on Iron Line Complex
Hudson – Non-thermal ionisation and Fe centroid energy
Schmahl – Erupting filament/looptop source of 17-June-03
Gallagher – Chromosphere and TR heating with CDS/RHESSI
Friday pm:
Gopalswamy – HXRs, EUV, delayed Type II/III of 6-June-02 (joint with 3)
McTiernan – Temperature of quiet corona using Fe Complex
Joint session with WG 1,3
Saturday am:
Fletcher – HXR/UV footpoints and magnetic field

7. using Fe, Fe/Ni complex (Phillips, Dennis)
IRON COMPLEX STUDIES
Variation of flare element abundances and hot coronal source properties
using Fe, Fe/Ni complex (Phillips, Dennis)
- Implement updates to atomic data/develop T diagnostic potential
- look for Fe abundance variations throughout flares + flare-to-flare
Search for signatures of coronal non-equilibrium ionisation with Fe (Hudson)
- search out very fast events – presumably further from equilibrium
- look for evidence of Fe complex centroid variations
Multi-instrument DEM of quiet corona (McTiernan)
- RHESSI quiet time data
- EIT and CDS synoptic data at lower temperatures

8. Energetics and Dynamics of RHESSI/CDS flares (Gallagher, Fletcher,
Energetics of pre- impulsive phase sources compared to eruption (Schmahl)
- set of RHESSI flares showing Ha filament ejection
- examine total energy of rise phase compared to filament KE
Energetics and Dynamics of RHESSI/CDS flares (Gallagher, Fletcher,
Dennis, Veronig)
- 5 CDS events identified
- derived v, F(E), Ne and T to be compared with hydromodels, Neupert predictions
Statistics of RHESSI Microflares (Krucker, Christe, Grigis)
- thermal and non-thermal characteristics of microflare population (already assembled)
- study of soft-hard-soft in these events
Spatial – Temporal structure of Acceleration (Grigis, Fletcher, Warmuth)
- Find UV/Ha data for Paolo’s 13 SHS events
- correlate UV/Ha spatial development with HXR time/spectral evolution

9. OVERALL MAGNETIC CONFIGURATION
Current sheets in the corona (Warmuth, Dennis, Holman, Sui)
- search for evidence for current sheets in Nancay data, LASCO, RHESSI
Origin of electrons in Type III bursts (Gopalswamy, Fletcher, Metcalf)
events showing delayed (wrt HXRs) Type III emission
understand topological changes, which may provide the open field lines
Location of HXR footpoints in overall magnetic structure (Fletcher, Metcalf)
set of flares occurring in July 2002, high cadence TRACE UV
magnetic extrapolations, HXR imaging and UV footpoint tracking
Propagating coronal waves (Hudson, Warmuth)
- Search for source of propagating waves (also in Yokhoh data)