Sweet Solar SAP: Boiling Down the Thermal Energy Content of Supra-Arcade Plasma Ashley Armstrong Advisor: Dr. Kathy Reeves Solar REU Summer 2012

Overview What are solar flares and how are they classified? Where and what is supra-arcade plasma? My work estimating the thermal energy of the supra-arcade plasma

What is a solar flare? Magnetic reconnection is assumed to drive flare events General brightening of electromagnetic spectrum Material in the flare reaches T≥10 7 K Often detected and classified by GOES

Solar Flare Model Reeves, ApJ, 2006 X Where’s the SAP?

X1.5 Flare in AR April 2002 TRACE 195Å

Prior Observations McKenzie & Hudson, ApJ, 1999 M January 1999 Yohkoh: SXT Gallagher, et al., Solar Physics, 2002 X April 2002 TRACE C4.9 5 November 2010 SDO: AIA AIA :47: Reeves & Golub, ApJ, 2011

Project Motivation Neupert Effect Implies peak X-ray flux will be directly proportional to total thermal energy released Reeves & Moats, ApJ, 2010 Found power law relation instead F peak ∼ E α (1.54 ≤ α ≤ 2.54) Hudson, Space Sci Review, HXT * GOES Derivative

Reeves & Moats, 2010 α = 2.54α = 2.16 α = 1.81α = 1.54 Reeves & Moats, ApJ, 2010

Project Goal Estimate the thermal energy content of supra- arcade plasma. Serves as approximation for the total thermal energy input into the flare Use observations to test modeling results E th = 3Nk b T

Location Near limb Not rotated behind disk GOES Class C, M, X Hottest Plasma Temperatures Present in 131 Å Absent from 171 Å Step 1: Event Selection

AIA Response Functions 131 Å 171 Å 131 Å Response Function171 Å Response Function Overlap Intensity (dn cm 5 / sec) Log Temperature (K)

Contrasting AIA Data AIA 131ÅAIA 171Å 8 March 2011

Date & TimeGOES Class 8 March 2011 Peak Time: 18:28 UT M4.4 8 March 2011 Peak Time: 20:16 UT M1.4 4 November 2011 Peak Time: 01:01 UT C5.4 Selected Events AIA 131 Å

Step 2: Capturing the SAP! AIA 131 Å 131 Å Contour335 Å ContourSAP Pixels 4 November :11:04UT

Step 2: Capturing the SAP! 18:56: November 3 X

Step 3: Estimate Line-of- Sight Utilizing STEREO A & B in 195 Å STEREO A 195 Å

Step 4: Finding Thermal Energy Content Assumptions Constant line-of-sight depth All plasma at T = 11 MK Data from SAP pixels Use emission measure of each pixel to obtain particle density (n) The number of pixels in SAP region and line-of-sight give an estimate of the volume (V) Total number of particles: N = nV E th = 3Nk b T EM ~ ∫n 2 dl

Results & Discussion

Model lines from Reeves & Moats, 2010

Conclusions Initial observations roughly support the power law relation between flux and thermal energy, as proposed by Reeves & Moats, 2010 Discrepancies exist between the thermal energy in the observations and modeling Future analysis of many more flares is needed before the power law relation can be conclusively supported

Acknowledgments Dr. Kathy Reeves NSF (grant number ATM ) NSF (grant number AGS ) (Plasma Heating During Coronal Mass Ejections, Nick Murphy PI). CFA Astronomy REU Coordinators and Dr. Ed Deluca SSXG & Admins Fellow astronomy and solar interns THANK YOU!

Questions ?