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 2.5x smaller than SXT) Extremely large dynamic range

XRT Temperature Coverage 9 X-ray filters + G-band in focal plane Broadest temperature range coverage of any imager to date

AR X-flares!

Downflows Observed with XRT TRACE 195 XRT med-Be

Pre-flare Configuration TRACE 195XRT thin-Be 12/14/ :54 UT

Post-flare Configuration TRACE 195XRT thin-Be 12/15/ :33 UT

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. DeLuca, 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 coronaflare loop

DEM Analysis ambient coronaflare loop

Emission Measures in Different Temperature Bins 2-3 MK3-5 MK5-10 MK

Emission Measures in Different Temperature Bins MK20-50 MK 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 Eruption Model ( Based on Lin & Forbes 2000) Arcade of 1D hydro loops Thermal energy generated here Input here See Reeves & Forbes, ApJ, 2005 Reeves et al., ApJ, submitted

Temperatures and Densities Temperature Density

Simulated XRT Intensities

Some Observations 2006/12/17 C2 flare 2007/01/12 C1.5 flare

Loop-top knots may be more than projection effects XRT should see evidence of different conduction fronts in flare plasma Modeling Conclusions

Stay tuned for more great XRT flare data as solar maximum approaches...