Flares and Eruptive Events Observed with the XRT
Flares and Eruptive Events Observed with the XRT on Hinode Kathy Reeves Harvard-Smithsonian Center for Astrophysics
Outline 1. Introduction to XRT 2. Some XRT flare observations 3. Temperature analysis of a small flare 4. Modeling XRT flare emission
The X-Ray Telescope • • The XRT is a collaborative effort between SAO (mirror, filters, structure and mechanical systems) and ISAS (camera sensor and electronics). The telescope is a modified Wolter I with a 35 cm aperture and a 2. 71 m focal length.
New XRT Capabilities • Unprecedented combination of field of view and image resolution (pixels 2. 5 x smaller than SXT) • Extremely large
XRT Temperature Coverage • 9 X-ray filters + G-band in focal plane • Broadest temperature range coverage of any imager to date
AR 0930 - 2 X-flares!
Downflows Observed with XRT TRACE 195 XRT med-Be
Pre-flare Configuration 12/14/2006 10: 54 UT TRACE 195 XRT thin-Be
Post-flare 12/15/2006 01: 33 UT Configuration TRACE 195 XRT thin-Be
Limb Flare
Field Line Shrinkage? Priest & Forbes, A&ARv, 2002
Coordinated XRT-SOT Flare Observations
Determining Temperatures • Useful for understanding location of flare heating, cooling processes in flares and solar eruptions. • Method 1 - Filter Ratios • Method 2 - Differential Emission Measure Analysis
Observations
Filter Ratio Analysis
Filter Ratios * * *
Filter Ratio Analysis
DEM Analysis • Method developed by M. Weber, E. De. Luca, L. Golub (see L. Golub et al. , 2004) • DEM determined by a least-squares minimization algorithm • Random error generation for determining DEM errors
DEM Analysis ambient corona flare loop
DEM Analysis ambient corona flare loop
Emission Measures in Different Temperature Bins 2 -3 MK 3 -5 MK 5 -10 MK
Emission Measures in Different Temperature Bins 10 -20 MK 20 -50 MK 50 -100 MK
Where is the Hot Plasma?
RHESSI Data Also useful for constraining DEM: TRACE, EIS, CDS, . . .
Conclusions so far. . . • Post-flare loops contain multi- thermal plasma, ambient corona is closer to two-temperature plasma • Hot plasma is not well determined using this method with only XRT data • RHESSI data should be useful in constraining high temperature plasma
Model of Solar Eruptions Thermal energy Input here generated here Arcade of 1 D hydro loops Eruption Model See Reeves & Forbes, Ap. J, 2 (Based on Lin & Forbes 2000) Reeves et al. , Ap. J, submitted
Temperatures and Densities Density Temperature
Simulated XRT Intensities
Some Observations 2006/12/17 C 2 flare 2007/01/12 C 1. 5 flare
Modeling Conclusions • Loop-top knots may be more than projection effects • XRT should see evidence of different conduction fronts in flare plasma
Stay tuned for more great XRT flare data as solar maximum approaches. . .
- Slides: 32