Preflare phenomena in HXR, SXR

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Preflare phenomena in HXR, SXR EUV
Ed Schmahl, Univ MD NASA/GSFC LSSP

• SUMMARY
• Previous Observations of Preflare
• 2003 Nov 03 Preflare SXR time profiles
• RHESSI time profiles
• Magnetic overview
• EIT Time Sequence
• RHESSI Preflare Images
• RHESSI Spectra
• MLSO WL RHESSI
• CONTEXT
• QUESTIONS, CONCLUSIONS

RHESSI WORKSHOP, LOCARNO, June 7-11, 2005
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• Preflare HXR
• HXIS
• Preflare Plasmoids
• SXT
• RHESSI
• Current Sheets

HXIS 3.5-5.5 keV Harrison, 1980
.
6-8, 10-12 16-20 keV Sui and Holman (2003)
Sui, PhD Thesis, 2004
RHESSI WORKSHOP, LOCARNO, June 7-11, 2005
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The derivative (bottom panel) of the 1-8 A flux
(top) should be similar to the impulsive HXR
profile.
RHESSI WORKSHOP, LOCARNO, June 7-11, 2005
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GOES EMISSION MEASURE TEMPERATURE
RHESSI WORKSHOP, LOCARNO, June 7-11, 2005
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RHESSI HXR TIME PROFILES
GOES 1-8 A DERIVATIVE
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MDI Magnetograms of AR 10488
s
Note the absence of any potentially confusing
behind-the-limb magnetic activity westward of AR
0488.
RHESSI WORKSHOP, LOCARNO, June 7-11, 2005
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CLEAN AND PIXON MAPS, 010130-010830 ut
RHESSI WORKSHOP, LOCARNO, June 7-11, 2005
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SXI and RHESSI preflare
Note SXI has pointing jitter and roll anomalies.
The roll has been roughly corrected, but the
jitter has not.
RHESSI WORKSHOP, LOCARNO, June 7-11, 2005
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EIT IMAGES OF PREFLARE AND FLARE PERIODS
004037
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005233
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010436
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011023
13

011807
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012359
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013016
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EIT RHESSI MOVIE
RHESSI WORKSHOP, LOCARNO, June 7-11, 2005
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RHESSI Preflare Maps 3-12 keV (color)12-25 keV
(contours)
010700-010830 010800-011030 011100
-011230
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RHESSI SPECTRA 5-50 keV Thermalbroken
powerlaw Preflare period 010200-011100

• Broken powerlaw extends down to 5 keV
• Thermal component never dominates
• EM and T are poorly determined
• Chisquare 1 if EM0

White photons, Green thermal model, Red
broken powerlaw, Purple background
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MLSO WL (vignetted) MOVIE
RHESSI WORKSHOP, LOCARNO, June 7-11, 2005
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Associated WL event 0120-0126 UT
Preflare HXR
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Putting the pieces together...
Vertical HXR structure
PREFLARE
SHOCK
CURRENT SHEET
FLARE ONSET
LOOPTOP SOURCE
EUV LOOP
Shibata's cartoon
RHESSI Looptop Source
FLARE DECAY
Kundu et al, this workshop
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• A FEW QUESTIONS RAISED BY THE OBSERVATIONS
• Is the pre-flare vertical HXR source a current
  sheet? Does this represent slow
  reconnection?
• Bright knots sites of tearing?
• Does the flare reconnection initiate the CME?
• Is the low-lying WL feature a plasmoid?
• Is this a breakout event?
• What is the underlying physics of the EUV
  loop changes? (interacting loops?) the
  power-law HXR spectrum? (thick/thin target?)
  the weak thermal emission? (delayed Neupert
  effect?)
• What are the energetics of
• the nonthermal/thermal pre-flare electrons?
• the EUV loops?
• the CME?

RHESSI WORKSHOP, LOCARNO, June 7-11, 2005