by Steven Christe, Sam Krucker, R. P. Lin
Space Sciences Laboratory, University of California, Berkeley, CA 94720
The Astrophysical Journal, Volume 680, Issue 2, pages 149-152 (ADS link)
Abstract
During a period of 12 minutes on 2002 July 19 14:23-14:35 UT, the WAVES instrument on WIND observed six interplanetary type III radio bursts, one approximately every 2 minutes, and each was accompanied by a weak hard X-ray (HXR) burst (12-15 keV) observed by RHESSI. The radio bursts are observed up to 150 MHz with some up to 600 MHz. Simultaneous observations by TRACE show jetlike eruptions emanating from the region of HXR emission. The observed HXRs are inconsistent with emission from the escaping type III-producing nonthermal electrons. We suggest that the type III acceleration process may be associated with an explosive release of <~5×1026 ergs in the form of a “superhot” (26 MK) thermal plasma in the corona, an energy comparable to that associated with the type III-producing electrons.
by Pascal Saint-Hilaire, Sam Krucker, Steven Christe, and Robert P. Lin
Space Sciences Laboratory, University of California, Berkeley, CA 94720
Received 2008 August 21; accepted 2009 February 2; published 2009 April 20
The Astrophysical Journal, Volume 696, Pages 941–952, 2009 (ADS link)
Abstract
We study the detectability and characterization of electron beams as they leave their acceleration site in the low
corona toward interplanetary space through their nonthermal X-ray bremsstrahlung emission. We demonstrate that
the largest interplanetary electron beams (1035 electrons above 10 keV) can be detected in X-rays with current and future instrumentation, such as RHESSI or the X-Ray Telescope (XRT) onboard Hinode. We make a list of optimal observing conditions and beam characteristics. Amongst others, good imaging (as opposed to mere localization or detection in spatially integrated data) is required for proper characterization, putting the requirement on the number of escaping electrons (above 10 keV) to 3
× 1036 for RHESSI, 3 × 1035 for Hinode/XRT, and 1033
electrons for the FOXSI sounding rocket scheduled to fly in 2011. Moreover, we have found that simple modeling
hints at the possibility that coronal soft X-ray jets could be the result of local heating by propagating electron
beams.
Steven Christe [1], S. Krucker [1], L. Glesener [1], B. Ramsey [2], T. Takahashi [3]
1 Space Sciences Lab, U.C. Berkeley
2 NASA/M.S.F.C., Huntsville
3 Astro-H team, Japan
Presented at SPIE 2009 (link)
Abstract
The Focusing Optics X-ray Solar Imager (FOXSI) is a NASA sounding rocket payload scheduled to fly in late 2010 to observe hard X-ray emission (HXR) from the quiet Sun. To date, the most sensitive HXR images are made using a rotating modulating collimator aboard the Reuven Ramaty High Energy Spectroscopic Imager satellite (RHESSI). However, the rotating modulation technique is intrinsically limited in sensitivity and dynamic range. FOXSI uses nested-shell, grazing-angle optics and silicon strip detectors to achieve an angular resolution of 12 arcsecs (FWHM) and ~1 keV energy resolution. FOXSI will be a pathfinder for future solar HXR observatories.
