RHESSI Paris workshop, July 2004

Working group 4: Multi-wavelength observations

ORGANIZATION

van Driel-Gesztelyi: wisdom and experience
Mandrini: Oct-Nov events 
Krucker: RHESSI footpoint motions w/ Boris
Somov: footpoint and coronal sources
Kudela: SONG gamma-rays
Dennis: Fe feature
Hudson: Oct-Nov energetics
Mrozek: Atmospheric response
Demoulin: magnetic anything, esp Oct 28
Berlicki: Oct 22 02, 28 Oct 03
Gallagher: Oct-Nov regions & flares
Allred: Lower atmosphere response
Khan: decimetric spikes
Bianda: Impact polarization, null results
Veronig: Oct-Nov, esp Nov. 3
Li: 20 Oct 03, atmospheric response
Benz: Atmospheric response (impact pol., footpoints)
Fletcher: Footpoints and magnetism
Temmer: Listening
Caspi: Fe lines
Kuzin: Soft X-rays

Fletcher: 
 * review of actions from past WG4 meetings (Taos)
 * draft timetable for this WG discussion

Berlicki: chromospheric emission in the late phase
 * NT electrons, thermal conduction, or radiative heating?
 * 22-oct-02 AR 0162 ~M1 max 15:30 UT
 * RHESSI, TRACE, THEMIS, CDS Fe XIX
 * RHESSI spectra starting at 16:03 show Fe but not Fe-Ni
Dennis comment: cannot readily believe the non-thermal component in
   such fits
 * Has revised HCK calculation for 10 keV cutoff
Discussion of time scale in NT/T comparison; discussion of fit uncertainty;
   background correction (Dennis et al)
Discussion of CDS results (Hudson et al) 
Discussion of time scale in thermal energy (Somov, Dennis, Gallagher, Benz, 
   Hudson) comparing energy and power
Discussion of time variability as T/NT discriminant (Demoulin)
 * Presentation of CDS data - surprising Si XII downflows in H-alpha ribbons?
   (probably not so clearly resolved because of temporal smoothing in 30-min
   CDS scans).
Discussion of ribbon behavior (Fletcher)
 * TRACE movie
 
Survey of Oct/Nov flares

Oct 20 03 (00484) EIT, RHESSI, chromospheric (H-alpha, 10830, Ca K, Ca II)
  Themis, 80-4000 MHz
Oct 28 03 (00486) RHESSI (decay), SONG, TRACE (195, 1600), Themis MSDP late,  
  polarization limit, H-alpha late phase, TSI/SORCE, MDI, Huairou 
Oct 29 03 (00486) RHESSI full event, SPIRIT, TRACE (1600 -> 195)
Nov  2 03 () RHESSI 
Nov  3 03
Nov  4 03 (00486) SONG, WL, etc, RHESSI missed the boat

FOOTPOINTS

Somov: footpoints
 * 72-event survey (@ HXT M2) from Yohkoh
 * automated processing of multiple sources
 * overlays on KPNO and MDI
 * find 3 types of motions in 80% of events:
   1) mainly away from simplified neutral line (5%) on both sides
   2) along the neutral line in opposite directions (26%)
   3) along, but parallel (30%)
 * RHESSI July 23 results
 * "Rainbow" reconnection model: S-shaped NL distortion from vortex flow;
   component perpendicular to NL drives reconnection
Discussion of "vortex flow" (Gallagher, Hudson, Fletcher, Van Driel)
 * strictly converging flow => standard model in 2D (category 1)
 * converging plus shear flow => opposite parallel case (2) 
Discussion of type 3 and observational confirmation (Demoulin - are they
   physically distinguished types, or a continuum; Hudson what about the
   observations) hope is that RHESSI and better data will improve the situation

Li: MISS at PMO
 * M1.9 20-oct-03 good RHESSI coverage @ A1
 * RHESSI observations with chromospheric and EIT observations 
 * GOES and RHESSI temperatures disagree - SH
Discussion of analysis techniques (Hudson, Dennis) > 30 keV background effect
Discussion of reality of non-thermal fit, density of loop (Veronig)
 * spectral analysis involving low-energy cutoff
Mention of Holman limit method for safe energetics analysis (Dennis)
Discussion of future development of theory: must incorporate atmospheric
  response (Fletcher, Demoulin, Dennis, Hudson)
Discussion of Jana Kasparova's flare (Dennis) with high cutoff energy,
  eg 50-60 keV
 * Conclusions: E_NT/E_T ~ V^0 (thin) or V^-.5 (thick)

Gallagher: overview of Oct-Nov events
 * X/M = 12/41 including huge ones
 * NOAA 10484 2/14
 * NOAA 10486 8/20 
 * NOAA 10488 2/7
 * see http://beauty.nascom.nasa.gov/~ptg/oct-nov-2003-xflares.html
   for much fuller information
 * an innovation: gradient maps automatically generated from MDI
 * analogy of following football by studying only the behavior of the grass 
Discussion of how to plot gradients (Hudson, Demoulin, Mandrini, many)
 * Note that the X28 was way above Zirin's area/magnitude plot
 * TIL behavior remarkable. Jet behavior remarkable.
 
Demoulin: magnetic magic for 28-oct-03 flare 
 * nice 2-ribbon example 28-oct-03 in TRACE 195
Discussion of where the energy is (Hudson says the impulsive phase)
 * magnetic field evolution; corridor with much shear flow... convergence
 * focus on two pre-events and ask if they represent destabilization
 * main features include two shear zones; initial confined event occurs
   just at this location. Representation by LFFF mimics the shear geometry
Discussion of "before" and "after" field lines (Fletcher, Hudson, Dennis)
  and how they might reconnect. This is based on EFR history somehow 
  (Gallagher, Fletcher, Van Driel, Mandrini)
 * you only see the "after", not the "before" because of energy release
Discussion of how one can be so sure of the particular changes (Dennis,
  Van Driel, Mandrini, Gallagher)
 * point out that ribbons should always map to separatrices, so that the
   general picure is eminently reasonable
Discussion of BP events (Dennis, Gallagher)
Discussion of where are the separatrices and ribbons, and whether the
  energy is growing or decaying during the "before/after" (Gallagher, Dennis,
  Fletcher, Mandrini) 
 * next precursor shows clear quadrupolar connectivity => "breakout" and
   identification of opening field lines
 * main event an hour later (X17!)
Discussion of behavior of separatrices in a true before/after field
  comparison (Hudson)
 * Conclusions: local reconnection due to EFR; four ribbons in global
quadrupolar reconnection; X17 flare with two ribbons; consistent with
either breakout or tether-cutting 
Discussion of how to distinguish TC and BO (Gallagher and chorus)
  "What does Spiro know (about the observations) [anyway]?" - Lidia

Kudela: Oct. 28
 * 12 minutes @ 4 sec resolution from SONG. Are there Integral data?
 * 2nd component at 11:06 extends to 60-100 MeV, associated with neutrons
 * Aug 25, 2001 had similar late component 

Bianda: preview of impact polarization limits (IRSOL)

Hudson: Oct. 28 total irradiance
 * .0287% times 600 sec ~6e32 ergs

Benz: Phoenix-2
 * gyrosynchrotron, II, "afterglow" 
 * afterglow consists of pulsations, type IV, drifting structure
 * Callisto long waves => 7.2e4 SFU, a record