Determining the spatial variation of accelerated electron spectra in solar flares

A. Gordon Emslie, G. J. Hurford, Eduard P. Kontar, Anna Maria Massone, Michele Piana, Marco Prato, Yan Xu

Research output: Chapter in Book/Report/Conference proceedingConference contribution

6 Scopus citations

Abstract

The RHESSI spacecraft images hard X-ray emission from solar flares with an angular resolution down to ∼ 2″ and an energy resolution of 1 keV For such a Rotating Modulation Collimator (RMC) instrument, imaging information is gathered not as a set of spatial images, but rather as a set of (energy-dependent) spatial Fourier components (termed visibilities). We report here on a novel technique which uses these spatial Fourier components in count space to derive, via a regularized spectral inversion process, the corresponding spatial Fourier components for the electron distribution, in such a way that the resulting electron visibilities, and so the images that are constructed from them, vary smoothly with electron energy E. "Stacking" such images then results in smooth, physically plausible, electron spectra for prominent features in the flare. Application of visibility-based analysis techniques has also permitted an assessment of the density and volume of the electron acceleration region, and so the number of particles it contains. This, plus information on the rate of particle acceleration to hard-X-ray-producing energies [obtained directly from the hard X-ray spectrum I(ε)] allows us to deduce the specific acceleration rate (particles s-1 per particle). The values of this key quantity are compared with the predictions of various electron acceleration scenarios.

Original languageEnglish (US)
Title of host publicationParticle Acceleration and Transport in the Heliosphere and Beyond - 7th Annual International Astrophysics Conference
Pages3-10
Number of pages8
DOIs
StatePublished - Sep 29 2008
Externally publishedYes
Event7th Annual International Astrophysics Conference on Particle Acceleration and Transport in the Heliosphere and Beyond - Kauai, HI, United States
Duration: Mar 7 2008Mar 13 2008

Publication series

NameAIP Conference Proceedings
Volume1039
ISSN (Print)0094-243X
ISSN (Electronic)1551-7616

Other

Other7th Annual International Astrophysics Conference on Particle Acceleration and Transport in the Heliosphere and Beyond
CountryUnited States
CityKauai, HI
Period3/7/083/13/08

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)

Keywords

  • Hard X-rays
  • Imaging spectroscopy
  • Particle acceleration

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