First Results from the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI)

1. First Resultsfrom the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) Brian Dennis GSFC 11/14/2002

2. HESSI PI and Co-Is Robert Lin University of California, Berkeley PI Gordon Hurford University of California, Berkeley Imaging Scientist Norman Madden LBNL, Berkeley Germanium Detectors Brian Dennis GSFC/682 Mission Scientist Carol Crannell GSFC/682 Education & Outreach Gordon Holman GSFC/682 Flare Theory Reuven Ramaty GSFC/661 Flare Theory Tycho von Rosenvinge GSFC/661 ACE Collaboration Alex Zehnder Paul Scherrer Inst. Switzerland Telescope design and fab. Frank van Beek Driebergen, The Netherlands Grids and Imaging Patricia Bornmann NOAA GOES Collaboration Richard Canfield Montana State University Ground-based Observations Gordon Emslie Univ. of Alabama, Huntsville Flare Theory Hugh Hudson Solar Physics Research Corp. Imaging Arnold Benz Inst. of Astronomy, Zurich, Switzerland Radio Observations John Brown Univ. of Glasgow, Scotland Flare Theory Shinzo Enome NAO, Japan Radio Observations Takeo Kosugi NAO, Japan Imaging Nicole Vilmer Observatoire de Paris, Meudon, France Data Analysis A1309.012

3. GSFC Involvement Science Dennis (682) Mission Scientist Holman (682), Phillips (NRC) Solar flare physics Sui, McArthur (CUA) Flare data analysis & modeling Crannell (682) Education & Public Outreach Imaging Clark (547) Imager metrology and testing Amato (544) Grid environmental testing Orwig (682) Optical & X-ray grid characterization Uribe, Berg, Bilodeau, Tolbert (ITSS/SSAI) Spectrometer Boyle, Shirey (552) Cryostat design, cooler evaluation Banks (OSC, 552) Flight-qualified Sunpower cooler Data Analysis Schwartz (SSAI) Data analysis software + Tolbert (SSAI) Graphical user interface + Schmahl (UMD) Image reconstruction Zarro, Gallagher (L3-Com) Complementary observations Bilodeau Spectroscopy software Berg Web site & student support A1309.014

6. RHESSI Spectral Coverage

7. Flare Energy Budget • “The >20 keV electrons contain 10 to 50% of the total energy output” Lin and Hudson (1976). • Not a single component of the energy budget “is presently known to better than an order of magnitude” (Hudson 1986). • Energy in electrons is uncertain because of lower energy cutoff to spectrum. • Thermal energy in plasma is uncertain because of uncertain volume, density, filling factor. • Only plasma in narrow temperature range is generally imaged.

13. RHESSI Light Curve

14. SOHO – TRACE – RHESSI MovieTom Bridgman, Scientific Visualization Studio, GSFC

15. Flare Model Cartoons • Grand Archive of Flare and CME Cartoons http://solarmuri.ssl.berkeley.edu/~hhudson/cartoons/ • Kopp and Pneuman ModelKopp and Pneuman, Solar Phys. 50, 85 (1976).

16. Shibata’s Flare ModelK. Shibata, Astrophys. and Space Science 264, 129, 1998

17. Three-dimensional magnetic reconnection Gosling, J. T., Birn, J., and Hesse, M., GRL 22, 869 (1995).

18. TRACE 195-Å Response TRACE response (DN cm5 s-1 pix-1) Fe XII Fe XXIV Temperature (K)

19. RHESSI – TRACE MovieGreen – white: TRACE 195 Å, Blue: RHESSI 50 – 100 keV, Red: 12 – 25 keV

20. RHESSI (12 – 25 keV) TRACE (195 Å) Overlay

21. RHESSI (12 – 25 keV) TRACE (195 Å) Overlay

22. Red:12 – 25 keV, blue: 50 – 100 keV - TRACE (195 Å)

23. Red:12 – 25 keV, blue: 50 – 100 keV - TRACE (195 Å)

25. Major Hard X-ray Peak04/21/2002 01:15:17.3 – 01:15:42.1 UTCleaned Maps

26. RHESSI Imaging Spectroscopy X1.5 Flare 21 April 2002 01:15 UT

27. RHESSI Imaging Spectroscopy E-3.2 E-7

28. The Neupert Effect • The time integral of the hard X-ray emission closely matches the temporal variation of the soft X-ray emission. • Implies that accelerated electrons that produce the hard X-rays also heat the plasma that produces the soft X-rays.

29. GOES Lightcurve

30. The Neupert Effect

31. RHESSI – GOES Comparison RHESSI25 – 50 keV GOES 1 – 8 Åtime derivative

33. B A C

34. TRACE light curves19.5 nm Region A B C RHESSI light curve25 – 50 keV

36. B A C

37. B A C

38. Summary • Energy in accelerated electrons > energy in SXR-emitting thermal plasma • Energy in electrons is a smaller fraction of thermal energy in smaller flares. • General agreement with Neupert Effect. • Poor spatial correlation between hard X-ray and EUV brightenings. • Long–duration energy release after SXR peak with no electron acceleration.

39. Summary • X-rays seen before TRACE brightening at same location • 3-25 keV X-rays start at 00:40 UT • TRACE 195Å brightening at 00:45 UT • >25 keV X-rays from site of TRACE ribbons • E-3.2 spectrum (S. Krucker) • Gradual variations, >1 min. time constant. • Neupert Effect • >25 keV time profile “matches” soft X-ray time derivative • Coronal X-ray source • Initially E-7 spectrum (S. Krucker) • Moves up for >12 hours after peak time • Initial velocity = 10 km s-1, changing to 1.7 km s-1 at ~03:00 UT • TRACE feature moves up at ~100 km s-1 (P. Gallagher) • LASCO CME velocity = 2500 km s-1 (G. Lawrence) • CME at Earth with velocity of 800 km s-1 (E. Roeloff) • >300 keV electrons seen with ACE injected at 01:33 UT (E. Roeloff)

40. Conclusions • RHESSI is operating almost flawlessly. • Over 3000 events listed in the RHESSI “flare” catalog. • Gamma-ray line flare detected on July 23. • Crab pulsar detected in June at time of closest approach. Image of nebula possible. • Several gamma-ray bursts detected with high energy resolution. • Hope for several years of observations – no consumables. • All data and analysis software freely available on line. • Please come help us to make full use of the observations!