RHESSI-Nessie II WG 3: “From sites of radiation to particle sources” Three sub-groups, to have...
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Transcript of RHESSI-Nessie II WG 3: “From sites of radiation to particle sources” Three sub-groups, to have...
RHESSI-Nessie II WG 3:“From sites of radiation to particle sources”
• Three sub-groups, to have appointed times in the program
• Specific educational questions to be shared and perhaps answered by Friday
• Collaborations leading to meaningful papers to be encouraged
Focus area #1: propagation
• “Realistic” magnetic fields: drifts, scattering, energy losses, trapping, Neupert effect
• Interested members? Fletcher, Galloway, Gordovskyy, Hannah, Hudson, Melnikov, Petrosian, Veronig
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Null?
Separatrices?
Anzer-Pneuman, 1982
Focus area #2: Radiation
1. “Realistic” magnetic fields: Microwave and X-ray luminosity, coronal emission, Alfven speeds, “cornucopia effect”
• Interested members? Fletcher, Gallagher, Hudson, Mann, McTiernan, Veronig, Warmuth
Focus area #3: Footpoint physics
• Particle penetration into the lower atmosphere. Positron creation and decay. DEM.
• Interested members? Allred, Brown, Fletcher, Hudson, Murphy, Ryan, Veronig, Woods
Tentative schedule, Team 3
Wednesday 11:00 - lunch Team organization; Propagation themeWednesday 14:00 - 16:00 Focus area #1: Radiation themeWednesday 16:30 - supper Focus area #2: Events
Thursday 09:30 - 10:30 Discussion of coronaThursday 11:00 - lunch Focus area #3: Footpoint physicsThursday 14:00 - 16:00 Propagation: answers to questionsThursday 16:30 - supper Radiation: answers to questions
Friday 09:00 - 10:30 Footpoints: answers to questionsFriday 11:00 - lunch Working session(s)Friday 14:00 - 16:00 Recap, followed by working session(s)
RHESSI current sheet?
• Sui & Holman, ApJ 2001
• Homologous flare to that discussed by Astrid
• Signature appears in two other events
• Current-sheet signatures in UVCS data
Propagation Questions
• To what extent are electron footpoints smeared out by drift motions? Being studied… maybe?
• To what extent can ions and electrons be separated spatially? Considerably
• Do separatrices correspond to ribbons, or (Metcalf et al, 2003) are they intriguingly related? Being studied
• Does trapping and Coulomb loss explain 34-GHz looptop sources? Being studied… probably?!
• At what time scale does the steady-state approximation break down? Experts discussing
Radiation Questions
• Does trapping and Coulomb loss explain 34-GHz looptop sources? Being studied… probably?!
• Can a coronal loop be dense enough to stop 60 keV electrons? Yes; new input to models
• Do RHESSI observatinos suggest a coronal current sheet? Yes… being studied
• Can “realistic” field extrapolations help to understand flare X-ray sources? Being studied
Footpoint Questions
• Do electron-heated atmospheres produce thick enough transition regions to explain the 511-keV line width? No
• Do proton-heated atmospheres produce thick enough transition-region material to explain the 511-keV line width? Being studied
• Do we understand footpoint DEMs well enough to explain ribbon radiation? Being studied
• Do we understand why hard X-ray footpoint structures are so concentrated in the ribbons? Being studied