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Related papers: Regularized energy-dependent solar flare hard x-ra…

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We present a new analytical technique, combining Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) high-resolution imaging and spectroscopic observations, to visualize solar flare emission as a function of spectral component…

Instrumentation and Methods for Astrophysics · Physics 2015-09-15 Amir Caspi , Albert Y. Shih , James M. McTiernan , Säm Krucker

Kontar et al. (2004) have shown how to recover mean source electron spectra in solar flares through a physical constraint regularization analysis of the bremsstrahlung photon spectra that they produce. They emphasize the use of non-square…

Astrophysics · Physics 2009-11-10 E. P. Kontar , A. G. Emslie , M. Piana , A. M. Massone , J. C. Brown

Regularized imaging spectroscopy was introduced for the construction of electron flux images at different energies from count visibilities recorded by the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI). In this work we seek…

Solar and Stellar Astrophysics · Physics 2023-11-14 Anna Volpara , Paolo Massa , Sam Krucker , A Gordon Emslie , Michele Piana , Anna Maria Massone

Recent progress in solar Hard X-ray (HXR) observations with RHESSI data and methods for spectral inversion allow us to study model-independent mean electron flux spectra in solar flares. We report several hard X-ray events observed by…

Astrophysics · Physics 2009-11-11 Eduard P. Kontar , John C. Brown

The time evolution of the spectral index and the non-thermal flux in 24 impulsive solar hard X-ray flares of GOES class M was studied in RHESSI observations. The high spectral resolution allows for a clean separation of thermal and…

Astrophysics · Physics 2007-05-23 Paolo C. Grigis , Arnold O. Benz

We investigate the signature of the photospheric albedo contribution in solar flare hard X-ray spectra, the effect of low energy cutoffs in electron spectra, and the directivity of hard X-ray emission. Using Ramaty High Energy Solar…

Astrophysics · Physics 2008-11-26 J. Kasparova , E. P. Kontar , J. C. Brown

Hard X-ray spectra in solar flares provide knowledge of the electron spectrum that results from acceleration and propagation in the solar atmosphere. However, the inference of the electron spectra from solar X-ray spectra is an ill-posed…

Astrophysics · Physics 2009-11-10 E. P. Kontar , M. Piana , A. M. Massone , A. G. Emslie , J. C. Brown

The Reuven Ramaty High Energy Spectroscopic Solar Imager (RHESSI) uses the rotational modulation principle to observe temporally, spatially, and spectrally resolved hard X ray and gamma ray images of solar flares. In order to track the…

Astrophysics · Physics 2009-11-10 Kaspar Arzner

In this paper we present new optimization strategies for the reconstruction of X-ray images of solar flares by means of the data collected by the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI). The imaging concept of the…

Instrumentation and Methods for Astrophysics · Physics 2014-06-26 S. Bonettini , M. Prato

We study the evolution of the spectral index and the normalization (flux) of the non-thermal component of the electron spectra observed by RHESSI during 24 solar hard X-ray flares. The quantitative evolution is confronted with the…

Astrophysics · Physics 2007-05-23 Paolo C. Grigis , Arnold O. Benz

Polarization measurements of hard X-rays from solar flares can provide a direct handle on the extent to which the accelerated electrons are beamed, which, in turn, has important implications for particle acceleration models. Past efforts to…

Astrophysics · Physics 2009-11-07 M. L. McConnell , J. M. Ryan , D. M. Smith , R. P. Lin , A. G. Emslie

Hard x-ray spectral breaks are explained in terms of a 1D model with a co-spatial return current. We study 19 flares observed by RHESSI (Ramaty High Energy Solar Spectroscopic Imager) with strong spectral breaks at energies around a few…

Solar and Stellar Astrophysics · Physics 2018-01-08 Meriem Alaoui , Gordon Holman

As it was shown by many authors, a slow decrease in X-rays observed during the decay phase of long duration flares (LDE) can be explained only by a magnetic reconnection and energy release ceaselessly ongoing in the coronal part of a flare.…

Solar and Stellar Astrophysics · Physics 2011-04-08 Sylwester Kolomanski , Zbigniew Koltun , Tomasz Mrozek , Urszula Bak-Steslicka

High-energy X-rays and gamma-rays from solar flares were discovered just over fifty years ago. Since that time, the standard for the interpretation of spatially integrated flare X-ray spectra at energies above several tens of keV has been…

The degree of linear polarization in solar flares has not yet been precisely determined despite multiple attempts to measure it with different missions. The high energy range in particular has very rarely been explored, due to its greater…

Astrophysics · Physics 2009-11-11 E. Suarez-Garcia , W. Hajdas , C. Wigger , K. Arzner , M. Guedel , A. Zehnder , P. Grigis

The observed hard X-ray (HXR) flux spectrum $I(\epsilon)$ from solar flares is a combination of primary bremsstrahlung photons $I_P(\epsilon)$ with a spectrally modified component from photospheric Compton backscatter of downward primary…

Astrophysics · Physics 2016-08-30 Eduard P. Kontar , Alec L. MacKinnon , Richard A. Schwartz , John C. Brown

X-rays are a valuable diagnostic tool for the study of high energy accelerated electrons. Bremsstrahlung X-rays produced by, and directly related to, high energy electrons accelerated during a flare, provide a powerful diagnostic tool for…

Solar and Stellar Astrophysics · Physics 2015-03-09 Natasha L. S. Jeffrey

Recent progress in the diagnosis of flare fast particles is critically discussed with the main emphasis on high resolution Hard X-Ray (HXR) data from RHESSI and coordinated data from other instruments. Spectacular new photon data findings…

Astrophysics · Physics 2009-11-11 John C. Brown , Eduard P. Kontar

Hard X-rays and gamma-rays are the most direct signatures of energetic electrons and ions in the sun's atmosphere which is optically thin at these energies and their radiation involves no coherent processes. Being collisional they are…

Astrophysics · Physics 2008-11-26 J. C. Brown , E. P. Kontar , A. M. Veronig

We investigate accelerated electron energy spectra for different sources in a large flare using simultaneous observations obtained with two instruments, the Nobeyama Radio Heliograph (NoRH) at 17 and 34 GHz, and the Reuven Ramaty High…

Solar and Stellar Astrophysics · Physics 2015-05-13 M. R. Kundu , V. V. Grechnev , S. M. White , E. J. Schmahl , N. S. Meshalkina , L. K. Kashapova
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