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Related papers: Kappa distribution and hard X-ray emission of sola…

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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

To solve a number of problems in solar physics related to mechanisms of energy release in solar corona parameters of hot coronal plasma are required, such as energy distribution, emission measure, differential emission measure, and their…

Solar and Stellar Astrophysics · Physics 2015-10-26 G. G. Motorina , E. P. Kontar

The origin of hard X-rays and gamma-rays emitted from the solar atmosphere during occulted solar flares is still debated. The hard X-ray emissions could come from flaring loop tops rising above the limb or Coronal Mass Ejections (CME) shock…

The non-Maxwellian $\kappa$-distributions have been detected in the solar transition region and flares. These distributions are characterized by a high-energy tail and a near-Maxwellian core and are known to have significant impact on the…

Solar and Stellar Astrophysics · Physics 2015-06-23 Elena Dzifčáková , Jaroslav Dudík , Pavel Kotrč , František Fárník , Alena Zemanová

We present the relation of the spatial distribution of H-alpha kernels with the distribution of hard X-ray (HXR) sources seen during the 2001 April 10 solar flare. This flare was observed in H-alpha with the (Sartorius) telescope at Kwasan…

We calculate the flux of radio, hard X-ray and UV radiation from clusters of galaxies as produced by synchrotron emission and Inverse Compton Scattering of electrons generated as secondaries in cosmic ray interactions in the intracluster…

Astrophysics · Physics 2011-08-09 P. Blasi , S. Colafrancesco

Solar flare electron acceleration is an efficient process, but its properties (mechanism, location) are not well constrained. Via hard X-ray (HXR) emission, we routinely observe energetic electrons at the Sun, and sometimes we detect…

Solar and Stellar Astrophysics · Physics 2023-10-09 Ross Pallister , Natasha L. S. Jeffrey

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…

Imaging spectroscopy in X-rays with RHESSI provide the possibility to investigate the spatial evolution of the X-ray emitting electron distribution and therefore to study the transport effects on energetic electrons during solar flares. We…

Solar and Stellar Astrophysics · Physics 2018-02-07 S. Musset , E. P. Kontar , N. Vilmer

X-ray observations are a direct diagnostic of fast electrons produced in solar flares, energized during the energy release process and directed towards the Sun. Since the properties of accelerated electrons can be substantially changed…

Solar and Stellar Astrophysics · Physics 2015-10-28 Natasha Jeffrey , Eduard Kontar , Gordon Emslie , Nicolas Bian

Observations with {\em RHESSI} have enabled the detailed study of the structure of dense hard X-ray coronal sources in solar flares. The variation of source extent with electron energy has been discussed in the context of streaming of…

Solar and Stellar Astrophysics · Physics 2015-06-19 Natasha L. S. Jeffrey , Eduard P. Kontar , Nicolas H. Bian , A. Gordon Emslie

Solar flare hard X-ray spectroscopy serves as a key diagnostic of the accelerated electron spectrum. However, the standard approach using the collisional cold thick-target model poorly constrains the lower-energy part of the accelerated…

Solar and Stellar Astrophysics · Physics 2019-02-05 Eduard P. Kontar , Natasha L. S. Jeffrey , A. Gordon Emslie

We study the non-thermal emissions in a solar flare occurring on 2003 May 29 by using RHESSI hard X-ray (HXR) and Nobeyama microwave observations. This flare shows several typical behaviors of the HXR and microwave emissions: time delay of…

Astrophysics · Physics 2009-11-13 T. Minoshima , T. Yokoyama , N. Mitani

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

We present observations of electron energization in magnetic reconnection outflows during the pre-impulsive phase of solar flare SOL2012-07-19T05:58. During a time-interval of about 20 minutes, starting 40 minutes before the onset of the…

Solar and Stellar Astrophysics · Physics 2019-03-06 Marina Battaglia , Eduard P. Kontar , Galina Motorina

Solar flares are efficient particle accelerators with a large fraction of released magnetic energy (10-50%) converted into energetic particles such as hard X-ray producing electrons. This energy transfer process is not well constrained,…

Solar and Stellar Astrophysics · Physics 2023-04-12 Morgan Stores , Natasha L. S. Jeffrey , James A. McLaughlin

Using fully relativistic GEANT4 simulation tool kit, the transport of energetic electrons generated in solar flares was Monte-Carlo simulated, and resultant bremsstrahlung gamma-ray spectra were calculated. The solar atmosphere was…

The imaging spectroscopy capabilities of the Reuven Ramaty high energy solar spectroscopic imager (RHESSI) enable the examination of the accelerated electron distribution throughout a solar flare region. In particular, it has been revealed…

Solar and Stellar Astrophysics · Physics 2018-04-25 Duncan J. Stackhouse , Eduard P. Kontar

Context: Solar flares release a large fraction of their energy into non-thermal electrons, but it is not clear where and how. Bremsstrahlung X-rays are observed from the corona and chromosphere. Aims: We aim to characterize the acceleration…

Astrophysics · Physics 2009-11-11 Marina Battaglia , Arnold O. Benz

The acceleration of thermal solar wind protons at spherical interplanetary shocks driven by coronal mass ejections is investigated. The solar wind velocity distribution is represented using $\kappa$-functions, which are transformed in…

Space Physics · Physics 2019-08-07 P. L. Prinsloo , R. D. Strauss , J. A. le Roux