NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
Thermal and Nonthermal Contributions to the Solar Flare X-Ray FluxThe relative thermal and nonthermal contributions to the total energy budget of a solar flare are being determined through analysis of RHESSI X-ray imaging and spectral observations in the energy range from approx. 5 to approx. 50 keV. The classic ways of differentiating between the thermal and nonthermal components - exponential vs. sources - can now be combined for individual flares. In addition, RHESSI's sensitivity down to approx. 4 keV and energy resolution of approx. 1 keV FWHM allow the intensities and equivalent widths of the complex of highly ionized iron lines at approx. 6.7 keV and the complex of highly ionized iron and nickel lines at approx. 8 keV to be measured as a function of time. Using the spectral line and continuum intensities from the Chianti (version 4.2) atomic code, the thermal component of the total flare emission can be more reliably separated from the nonthermal component in the measured X-ray spectrum. The abundance of iron can also be determined from RHESSI line-to-continuum measurements as a function of time during larger flares. Results will be shown of the intensity and equivalent widths of these line complexes for several flares and the temperatures, emission measures, and iron abundances derived from them. Comparisons will be made with 6.7-keV Fe-line fluxes measured with the RESIK bent crystal spectrometer on the Coronas-F spacecraft operating in third order during the peak times of three flares (2002 May 31 at 00:12 UT, 2002 December 2 at 19:26 UT, and 2003 April 26 at 03:OO UT). During the rise and decay of these flares, RESIK was operating in first order allowing the continuum flux to be measured between 2.9 and 3.7 keV for comparison with RHESSI fluxes at its low-energy end.
Document ID
20040073450
Acquisition Source
Goddard Space Flight Center
Document Type
Preprint (Draft being sent to journal)
Authors
Dennis, Brian R.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Phillips, K. J. H.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Sylwester, Janusz
Sylwester, Barbara
Schwartz, Richard A.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Tolbert, A. Kimberley
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Date Acquired
August 21, 2013
Publication Date
January 1, 2004
Subject Category
Solar Physics
Meeting Information
Meeting: COSPAR (Committee on Space Research)
Location: Paris
Country: France
Start Date: July 16, 2004
End Date: August 1, 2004
Sponsors: Committee on Space Research
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

Available Downloads

There are no available downloads for this record.
No Preview Available