scholarly journals Models of Flaring Loops

1989 ◽  
Vol 104 (1) ◽  
pp. 105-115
Author(s):  
A. Gordon Emslie
Keyword(s):  
Solar Flares ◽  
Energy Transport ◽  
High Energy ◽  
Loop Structure ◽  
Predominant Role ◽  
Release Process ◽  
Flare Loop ◽  
X Ray ◽  
Physical Mechanisms ◽  
High Energy Electrons

AbstractWe review the somewhat questionable concept of an isolated flare loop and the various physical mechanisms believed to be responsible, to some degree, for energy transport within the loop structure. Observational evidence suggests a predominant role for high-energy electrons as an energy transport mechanism, and we explore the consequences of such a scenario in some detail, focusing on radiation signatures in the soft X-ray, hard X-ray, and EUV wavebands, as observed by recent satellite observatories. We find that the predictions of flare loop models are in fact in excellent agreement with these observations, reinforcing both the notion of the loop as a fundamental component of solar flares and the belief that electron acceleration is an integral part of the flare energy release process.

scholarly journals Major solar flares without coronal mass ejections

2008 ◽  
Vol 4 (S257) ◽  
pp. 283-286 ◽  
Author(s):  
N. Gopalswamy ◽  
S. Akiyama ◽  
S. Yashiro
Keyword(s):  
Open Field ◽  
Coronal Mass Ejections ◽  
Solar Flares ◽  
Active Regions ◽  
High Energy ◽  
X Ray ◽  
Type Iii ◽  
High Energy Electrons ◽  
Field Lines ◽  
Microwave Bursts

AbstractWe examine the source properties of X-class soft X-ray flares that were not associated with coronal mass ejections (CMEs). All the flares were associated with intense microwave bursts implying the production of high energy electrons. However, most (85%) of the flares were not associated with metric type III bursts, even though open field lines existed in all but two of the active regions. The X-class flares seem to be truly confined because there was no material ejection (thermal or nonthermal) away from the flaring region into space.

scholarly journals Plasma heating in the initial phase of solar flares

2009 ◽  
Vol 5 (S264) ◽  
pp. 282-284
Author(s):  
P. Rudawy ◽  
M. Siarkowski ◽  
R. Falewicz
Keyword(s):  
Solar Flares ◽  
Energy Transport ◽  
Electron Beams ◽  
Plasma Heating ◽  
Impulsive Phase ◽  
Thermal Electron ◽  
Flare Loop ◽  
X Ray ◽  
Heating Source ◽  
Rise Phase

AbstractIn this paper we analyze soft and hard X-ray emission of the 2002 September 20 M1.8 GOES class solar flare observed by RHESSI and GOES satellites, where soft X-ray emission precedes the onset of the main bulk hard X-ray emission by ~5 min. This suggests that an additional heating mechanism may be at work at the early beginning of the flare. However RHESSI spectra indicate presence of the non-thermal electrons also before impulsive phase. So, we assumed that a dominant energy transport mechanism during rise phase of solar flares is electron beam-driven evaporation. We used non-thermal electron beams derived from RHESSI spectra as the heating source in a hydrodynamic model of the analyzed flare. We showed that energy delivered by non-thermal electron beams is sufficient to heat the flare loop to temperatures in which it emits soft X-ray closely following the GOES 1–8 Å light-curve.

High energy electrons detected during solar flares

Solar Physics ◽  
1972 ◽  
Vol 23 (2) ◽  
pp. 487-500 ◽  
Author(s):  
C. Dilworth ◽  
D. Maccagni ◽  
F. Perotti ◽  
E. G. Tanzi ◽  
J. P. Mercier ◽  
...  
Keyword(s):  
Solar Flares ◽  
High Energy ◽  
High Energy Electrons

scholarly journals Detection of TeV Gamma Rays from SN1006

1998 ◽  
Vol 188 ◽  
pp. 121-124 ◽  
Author(s):  
Toru Tanimori
Keyword(s):  
Magnetic Field ◽  
Cosmic Rays ◽  
Gamma Rays ◽  
High Energy ◽  
Shock Acceleration ◽  
Emission Region ◽  
X Ray ◽  
High Energy Electrons ◽  
Tev Gamma Rays ◽  
The Magnetic Field

In spite of the recent progress of high energy gamma-ray astronomy, there still remains quite unclear and important problem about the origin of cosmic rays. Supernova remnants (SNRs) are the favoured site for cosmic rays up to 1016 eV, as they satisfy the requirements such as an energy input rate. But direct supporting evidence is sparse. Recently intense non-thermal X-ray emission from the rims of the Type Ia SNR SN1006 (G327.6+14.6) has been observed by ASCA (Koyama et al. 1995)and ROSAT (Willingale et al. 1996), which is considered, by attributing the emission to synchrotron radiation, to be strong evidence of shock acceleration of high energy electrons up to ~100 TeV. If so, TeV gamma rays would also be expected from inverse Compton scattering (IC) of low energy photons (mostly attributable to the 2.7 K cosmic background photons) by these electrons. By assuming the magnetic field strength (B) in the emission region of the SNR, several theorists (Pohl 1996; Mastichiadis 1996; Mastichiadis & de Jager 1996; Yoshida & Yanagita 1997) calculated the expected spectra of TeV gamma rays using the observed radio/X-ray spectra. Observation of TeV gamma rays would thus provide not only the further direct evidence of the existence of very high energy electrons but also the another important information such as the strength of the magnetic field and diffusion coefficient of the shock acceleration. With this motivation, SN1006 was observed by the CANGAROO imaging air Cerenkov telescope in 1996 March and June, also 1997 March and April.

Combined multiparametric X-ray diffraction diagnostics of microdefects in silicon crystals after irradiation by high-energy electrons

2013 ◽  
Vol 7 (3) ◽  
pp. 523-530 ◽  
Author(s):  
E. N. Kislovskii ◽  
V. B. Molodkin ◽  
S. I. Olikhovskii ◽  
E. G. Len ◽  
B. V. Sheludchenko ◽  
...  
Keyword(s):  
High Energy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Silicon Crystals ◽  
High Energy Electrons

scholarly journals Symmetric and triangle-shaped variability of blazars

2014 ◽  
Vol 10 (S313) ◽  
pp. 97-98
Author(s):  
Kenji Yoshida
Keyword(s):  
Gamma Ray ◽  
High Energy ◽  
Low Energy ◽  
Light Curves ◽  
X Ray ◽  
High Energy Electrons ◽  
Flux Variability ◽  
Low Energy Electrons ◽  
Flux Increase ◽  
Rise Phase

AbstractSymmetric and triangle-shaped flux variability in X-ray and gamma-ray light curves is observed from many blazars. We derived the X-ray spectrum changing in time by using a kinetic equation of high energy electrons. Giving linearly changing the injection of low energy electrons into accelerating and emitting region, we obtained the preliminary results that represent the characteristic X-ray variability of the linear flux increase with hardening in the rise phase and the linear decrease with softening in the decay phase.

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