What Affects the Power‐Law Distribution of the X‐Ray Solar Flares? A Theoretical Study Based on a Model of Uniform Normal Field

1999 ◽  
Vol 527 (2) ◽  
pp. 958-966 ◽  
Author(s):  
Yung‐Ping Chou
Keyword(s):  
Power Law ◽  
Solar Flares ◽  
Theoretical Study ◽  
Power Law Distribution ◽  
X Ray ◽  
Normal Field

The breakdown of the power-law frequency distributions for the hard X-ray peak count rates of solar flares

2013 ◽  
Vol 13 (12) ◽  
pp. 1482-1492 ◽  
Author(s):  
You-Ping Li ◽  
Wei-Qun Gan ◽  
Li Feng ◽  
Si-Ming Liu ◽  
A. Struminsky
Keyword(s):  
Power Law ◽  
Solar Flares ◽  
Frequency Distributions ◽  
X Ray ◽  
Peak Count

Theoretical Study of the Spatially Resolved Soft X‐Ray versus Hard X‐Ray Relationship in Solar Flares

1997 ◽  
Vol 491 (1) ◽  
pp. 395-401 ◽  
Author(s):  
Peng Li ◽  
James M. McTiernan ◽  
A. Gordon Emslie
Keyword(s):  
Solar Flares ◽  
Theoretical Study ◽  
X Ray ◽  
Spatially Resolved

scholarly journals Electrons and X-Ray Emission of Solar Flares

1990 ◽  
Vol 142 ◽  
pp. 409-413
Author(s):  
V. G. Kurt
Keyword(s):  
Solar Activity ◽  
Statistical Analysis ◽  
Solar Flare ◽  
Frequency Dependence ◽  
Power Law ◽  
Solar Flares ◽  
X Rays ◽  
Fast Electrons ◽  
X Ray ◽  
Flare Frequency

A statistical analysis of solar flare X-rays and interplanetary particle fluxes, measured onboard VENERA-13, 14 Spacecraft, was performed. The correlation of fluences for different manifestations of solar flares is strong, especially for fast electrons and hard and soft X-ray emissions. Frequency dependence on fluence value ϵi for practically all Kinds of solar flare emission can be described by power law ν (ϵ > ϵO) ∼ ϵ−0.45±0.15 which does not change significantly with solar activity. For different Hα flare importances the values of ϵi were obtained. It is proposed that appearance of certain energy flare frequency is strongly dependent on some scale factor.

scholarly journals Unravelling the unusually curved X-ray spectrum of RGB J0710 + 591 using AstroSat observations

2019 ◽  
Vol 492 (1) ◽  
pp. 796-803
Author(s):  
Pranjupriya Goswami ◽  
Atreyee Sinha ◽  
Sunil Chandra ◽  
Ranjeev Misra ◽  
Varsha Chitnis ◽  
...  
Keyword(s):  
Power Law ◽  
Wide Band ◽  
Lorentz Factor ◽  
High Energy ◽  
Power Law Distribution ◽  
Large Area ◽  
X Ray ◽  
Curvature Parameter ◽  
The One ◽  
Area X

ABSTRACT We report the analysis of simultaneous multiwavelength data of the high-energy-peaked blazar RGB J0710 + 591 from the Large Area X-ray Proportional Counters, Soft X-ray focusing Telescope, and Ultraviolet Imaging Telescope (UVIT) instruments onboard AstroSat. The wide band X-ray spectrum (0.35–30 keV) is modelled as synchrotron emission from a non-thermal distribution of high-energy electrons. The spectrum is unusually curved, with a curvature parameter βp ∼ 6.4 for a log parabola particle distribution, or a high-energy spectral index p2 > 4.5 for a broken power-law distribution. The spectrum shows more curvature than an earlier quasi-simultaneous analysis of Swift–XRT/NuSTAR data where the parameters were βp ∼ 2.2 or p2 ∼ 4. It has long been known that a power-law electron distribution can be produced from a region where particles are accelerated under Fermi process and the radiative losses in acceleration site decide the maximum attainable Lorentz factor, γmax. Consequently, this quantity decides the energy at which the spectrum curves steeply. We show that such a distribution provides a more natural explanation for the AstroSat data as well as the earlier XRT/NuSTAR observation, making this as the first well-constrained determination of the photon energy corresponding to γmax. This in turn provides an estimate of the acceleration time-scale as a function of magnetic field and Doppler factor. The UVIT observations are consistent with earlier optical/UV measurements and reconfirm that they plausibly correspond to a different radiative component than the one responsible for the X-ray emission.

scholarly journals Impulsive radio and hard X-ray emission from an M-class flare

2018 ◽  
Vol 615 ◽  
pp. A48
Author(s):  
Ping Zhang ◽  
Yang Guo ◽  
Lu Wang ◽  
Siming Liu
Keyword(s):  
Power Law ◽  
Impulsive Phase ◽  
High Energy ◽  
X Rays ◽  
Power Law Model ◽  
Power Law Distribution ◽  
Energetic Electrons ◽  
X Ray ◽  
Nonlinear Force ◽  
Class Flare

Context. Impulsive radio and hard X-ray emission from large solar flares are usually attributed to a hard distribution of high-energy electrons accelerated in the energy dissipation process of magnetic reconnection. Aims. We report the detection of impulsive radio and hard X-ray emissions produced by a population of energetic electrons with a very soft distribution in an M-class flare: SOL2015-08-27T05:45 . Methods. The absence of impulsive emission at 34 GHz and hard X-ray emission above 50 keV and the presence of distinct impulsive emission at 17 GHz and lower frequencies and in the 25–50 keV X-ray band imply a very soft distribution of energetic electrons producing the impulsive radio emission via the gyro-synchrotron process, and impulsive X-rays via bremsstrahlung. Results. The spectrum of the impulsive hard X-ray emission can be fitted equally well with a power-law model with an index of ∼6.5 or a super-hot thermal model with a temperature as high as 100 MK. Imaging observations in the extreme-UV and X-ray bands and extrapolation of the magnetic field structure using a nonlinear force-free model show that energetic electrons trapped in coronal loops are responsible for these impulsive emissions. Conclusions. Since the index of the power-law model is nearly constant during the impulsive phase, the power-law distribution or the super-hot component should be produced by a bulk energization process such as the Fermi and betatron acceleration of collapsing magnetic loops.

scholarly journals A Semianalytic Afterglow with Thermal Electrons and Synchrotron Self-Compton Emission

2022 ◽  
Vol 924 (1) ◽  
pp. 40
Author(s):  
Donald C. Warren ◽  
Maria Dainotti ◽  
Maxim V. Barkov ◽  
Björn Ahlgren ◽  
Hirotaka Ito ◽  
...  
Keyword(s):  
Power Law ◽  
Gamma Ray ◽  
Early Time ◽  
Spectral Structure ◽  
Power Law Distribution ◽  
X Ray ◽  
Broadband Emission ◽  
Dependent Form ◽  
Order Of Magnitude ◽  
Tev Gamma Rays

Abstract We extend previous work on gamma-ray burst afterglows involving hot thermal electrons at the base of a shock-accelerated tail. Using a physically motivated electron distribution based on first-principles simulations, we compute the broadband emission from radio to TeV gamma rays. For the first time, we present the effects of a thermal distribution of electrons on synchrotron self-Compton emission. The presence of thermal electrons causes temporal and spectral structure across the entire observable afterglow, which is substantively different from models that assume a pure power-law distribution for the electrons. We show that early-time TeV emission is enhanced by more than an order of magnitude for our fiducial parameters, with a time-varying spectral index that does not occur for a pure power law of electrons. We further show that the X-ray closure relations take a very different, also time-dependent, form when thermal electrons are present; the shape traced out by the X-ray afterglows is a qualitative match to observations of the traditional decay phase.

Statistical properties of starspots on solar-type stars and their correlation with flare activity

2018 ◽  
Vol 14 (A30) ◽  
pp. 369-372
Author(s):  
Hiroyuki Maehara
Keyword(s):  
Power Law ◽  
Solar Flares ◽  
Magnetic Activity ◽  
Statistical Properties ◽  
Flare Activity ◽  
The Sun ◽  
Power Law Distribution ◽  
Physical Processes ◽  
Energy Distributions ◽  
Solar Type

AbstractWe analyzed the statistical properties of starspots on solar-type stars and the correlation between properties of starspots and flare activity using observations from the Kepler mission. We found the size distribution of starspots on solar-type stars shows the power-law distribution and both size distributions of starspots on slowly-rotating solar-type stars and of relatively large sunspots are roughly lie on the same power-law line. We also found that the frequency-energy distributions for superflares and solar flares from spots with different sizes are the same for solar-type stars and the Sun. These results suggest that the magnetic activity on solar-type stars and that on the Sun are caused by the same physical processes

scholarly journals On the power-law distributions of X-ray fluxes from solar flares observed withGOES

2016 ◽  
Vol 16 (10) ◽  
pp. 161
Author(s):  
You-Ping Li ◽  
Li Feng ◽  
Ping Zhang ◽  
Si-Ming Liu ◽  
Wei-Qun Gan
Keyword(s):  
Power Law ◽  
Solar Flares ◽  
X Ray ◽  
Power Law Distributions

scholarly journals X-ray Radiation from Flare-heated Coronal Plasma

2000 ◽  
Vol 195 ◽  
pp. 395-396
Author(s):  
M. Güdel
Keyword(s):  
Power Law ◽  
Coronal Loop ◽  
Emission Measure ◽  
Magnetic Loop ◽  
Coronal Plasma ◽  
Power Law Distribution ◽  
Temperature Dependent ◽  
X Ray

We investigate the reaction of a coronal loop in the case of repetitive flares, with a power-law distribution in energy, injected into a rigid magnetic loop. Emission measure distributions and temperature-dependent modulations of the radiation are briefly discussed.

The occurrence of single hard x-ray sources in solar flares

2003 ◽  
Vol 32 (12) ◽  
pp. 2483-2488
Author(s):  
C GOFF ◽  
S MATTHEWS ◽  
L HARRA
Keyword(s):  
Solar Flares ◽  
X Ray
Sign in / Sign up

Export Citation Format

Share Document