scholarly journals Analysis of Prognoz - 9 Solar Flare Hard X-ray Data-support for the Non-thermal thick target Model

1990 ◽  
Vol 142 ◽  
pp. 445-447
Author(s):  
R. R. Rausaria ◽  
Ranjana Bakaya ◽  
P.N. Khosa
Keyword(s):  
Solar Flare ◽  
Energy Range ◽  
Spectral Index ◽  
High Energy ◽  
Thick Target ◽  
Low Energy ◽  
X Ray ◽  
Target Model ◽  
Data Support ◽  
Peak Emission

Solar flare hard X-ray data obtained by Prognoz-9 spacecraft (Abrosimov et al 1988) in the energy range 10-200 keV are analysed. In examples of events which we consider here, high energy X-ray pulses appear earlier than low energy ones, which is contrary to many other events where the low energy X-ray peak emission takes place earlier. The variation of the spectral index was dynamical.

scholarly journals The First Results from “Solar X-ray Spectrometer (SOXS)” Mission

2005 ◽  
Vol 13 ◽  
pp. 622-622 ◽  
Author(s):  
Rajmal Jain ◽  
Hemant Dave ◽  
P. Sreekumar ◽  
A. B. Shah ◽  
N. M. Vadher ◽  
...  
Keyword(s):  
Solid State ◽  
Solar Flare ◽  
Energy Range ◽  
Solar Flares ◽  
High Energy ◽  
Low Energy ◽  
Energy Detector ◽  
X Ray ◽  
Phoswich Detector ◽  
First Results

Abstract“Solar X-ray Spectrometer (SOXS)” mission on-board GSAT-2 Indian spacecraft was launched on 08 May 2003 by GSLV-D2 and deployed in geostationery orbit to study the X-ray emission from solar flares with high spectral and temporal resolution. The SOXS consists of two independent payloads viz. SOXS Low Energy Detector (SLD) payload, and SOXS High Energy Detector (SHD) payload. The SLD consists of two solid state detectors Si PIN and CZT, which cover the energy range from 4-60 keV, while the SHD has NaI(Tl)/CsI(Na) sandwiched phoswich detector that covers energy range from 20 keV to 10 MeV. We present very briefly the science objectives and instrumentation of SLD payload. After the successful In-orbit Tests (IOT), the first light was fed into SLD payload on 08 June 2003 when the solar flare was already in progress. We briefly present the first results from the SLD payload.

scholarly journals The high-energy flare plasma

1968 ◽  
Vol 35 ◽  
pp. 480-482
Author(s):  
C. De Jager
Keyword(s):  
Solar Flare ◽  
Energy Range ◽  
High Energy ◽  
Radio Observations ◽  
X Ray ◽  
Flare Plasma ◽  
Optical Flare

A solar flare has various aspects: the optical flare is often associated with emissions in the microwave or X-ray regions: this indicates the occurrence of a highly excited plasma, which we call the high-energy flare plasma. The existence of the high-energy flare plasma was first shown by radio observations in the microwave regions (Hachenberg) and later confirmed by X-ray observations in the energy range 102–106 eV.

THE DOPPLER FACTORS AT X-RAY BAND OF THE BLAZARS

2005 ◽  
Vol 14 (06) ◽  
pp. 947-956
Author(s):  
D. C. MEI ◽  
L. ZHANG
Keyword(s):  
Synchrotron Radiation ◽  
Energy Range ◽  
High Energy ◽  
Low Energy ◽  
X Rays ◽  
X Ray ◽  
Inverse Compton Scattering ◽  
Inverse Compton ◽  
Doppler Factor ◽  
Intrinsic Radiation

We study the Doppler factors for a group blazars at soft X-ray band. In our estimates, we have made the assumptions that (i) blazars can be divided into high-energy-peaked (HEP) objects whose synchrotron peak frequencies νp > 1014.7 Hz , and the low-energy-peaked (LEP) objects whose synchrotron peak frequencies νp≤1014.7 Hz , and (ii) the intrinsic radiation from a blazar in the energy range from radio to soft X-ray bands is the synchrotron radiation for HEP objects and the soft X-ray emission comes from inverse Compton scattering for LEP objects. Under the above assumptions, we estimate Doppler factors at optical (δO) and X-rays (δx) for 54 blazars by using the known radio Doppler factors and the observed flux densities in radio, optical and X-ray bands, and Doppler factors [Formula: see text] at X-ray band in which X-rays are assumed to be produced only by the synchrotron radiation. We get [Formula: see text] . The Doppler factors are different in various wavebands, and on average, the Doppler factor decreases with frequency from radio to X-ray bands.

Solar Energetic Electron Events Associated with Hard X-ray Flares 

2021 ◽  
Author(s):  
Wen Wang ◽  
Linghua Wang ◽  
Sam Krucker ◽  
Glenn M. Mason ◽  
Yang Su ◽  
...  
Keyword(s):  
Spectral Index ◽  
Power Law ◽  
Heliocentric Distance ◽  
Energetic Electron ◽  
High Energy ◽  
Thick Target ◽  
The Other ◽  
Ion Acceleration ◽  
X Ray ◽  
Positive Correlation

<p><span>We investigate 16 solar energetic electron (SEE) events measured by WIND/3DP with a double power-law spectrum and the associated western hard X-ray (HXR) flares measured by RHESSI with good count statistics, from 2002 February to 2016 December. In all 16 cases, the presence of an SEE power-law spectrum extending down to </span><span>6</span><span>5 keV at 1 AU implies that the SEE source would be high in the corona, at a heliocentric distance of </span><span>></span><span>1.3 </span><span>solar radii</span><span>, while the footpoint or footpoint-like emissions shown in HXR images suggest that the observed HXRs are likely produced mainly by thick target bremsstrahlung processes very low in the corona. </span><span>We find that in 8 cases (the other 8 cases), the power-law spectral index of HXR-producing electrons, estimated under the relativistic thick-target bremsstrahlung model, is significantly larger than (similar to) the observed high-energy spectral index of SEEs, with a positive correlation. In addition, the estimated number of SEEs is only </span><span>∼</span><span>10</span><span>-</span><span>4 </span><span>- </span><span>10</span><span>-</span><span>2 </span><span>of the estimated number of HXRproducing electrons at energies above 30 keV, but also with a positive correlation. </span><span>These results suggest that in these cases, SEEs are likely formed by upward-traveling electrons from an acceleration source high in the corona, while their downward-traveling counterparts may undergo a secondary acceleration before producing HXRs via thick-target bremsstrahlung processes. In addition, the associated </span><span>3</span><span>He</span><span>=</span><span>4</span><span>He ratio is positively correlated with </span><span>the observed high-energy spectral index of SEEs</span><span>, indicating a possible relation of the </span><span>3</span><span>He ion acceleration with high-energy SEEs</span></p>

Rise Time of Hard X-Ray Bursts

1975 ◽  
Vol 68 ◽  
pp. 237-238
Author(s):  
Joan Vorpahl ◽  
Tatsuo Takakura
Keyword(s):  
Spectral Index ◽  
Rise Time ◽  
Empirical Relation ◽  
Impulsive Phase ◽  
Alternative Interpretation ◽  
Thick Target ◽  
Thin Target ◽  
X Ray ◽  
Target Model ◽  
Acceleration Rate

SummaryA study was made of the hard X-ray component in the impulsive phase of solar flares. In 36 randomly chosen events the value for the slope in the differential electron power spectrum E−δ electrons cm−2 s−1 keV−1, was related to the 20–32 keV spike rise time (e-folding) as trise = 0.56 exp (0.88δ) in the thin target model and tfrise = 0.10 exp (0.88δ) in the thick target picture. In the thin target model, the above empirical relation would imply that the acceleration of electrons can be longer when the acceleration rate is smaller. An alternative interpretation would be that an impulsive hard X-ray burst is a superposition of two components emitted from thin and thick targets; when the former predominates, the duration is longer and the photon spectral index is larger, while when the latter predominates, the duration is shorter and the photon spectral index is smaller; 3 ≲δ ≲4 is required (Figure 1). The uncertainty in δ is 0.5 while that in the rise time is 1 s.

scholarly journals Combination of Dual-Energy X-ray Transmission and Variable Gas-Ejection for the In-Line Automatic Sorting of Many Types of Scrap in One Measurement

2021 ◽  
Vol 11 (10) ◽  
pp. 4349
Author(s):  
Tianzhong Xiong ◽  
Wenhua Ye ◽  
Xiang Xu
Keyword(s):  
High Efficiency ◽  
Nearest Neighbor ◽  
High Energy ◽  
Dual Energy ◽  
Center Of Gravity ◽  
Low Energy ◽  
Identification Accuracy ◽  
Flow Process ◽  
X Ray ◽  
Automatic Sorting

As an important part of pretreatment before recycling, sorting has a great impact on the quality, efficiency, cost and difficulty of recycling. In this paper, dual-energy X-ray transmission (DE-XRT) combined with variable gas-ejection is used to improve the quality and efficiency of in-line automatic sorting of waste non-ferrous metals. A method was proposed to judge the sorting ability, identify the types, and calculate the mass and center-of-gravity coordinates according to the shading of low-energy, the line scan direction coordinate and transparency natural logarithm ratio of low energy to high energy (R_value). The material identification was satisfied by the nearest neighbor algorithm of effective points in the material range to the R_value calibration surface. The flow-process of identification was also presented. Based on the thickness of the calibration surface, the material mass and center-of-gravity coordinates were calculated. The feasibility of controlling material falling points by variable gas-ejection was analyzed. The experimental verification of self-made materials showed that identification accuracy by count basis was 85%, mass and center-of-gravity coordinates calculation errors were both below 5%. The method proposed features high accuracy, high efficiency, and low operation cost and is of great application value even to other solid waste sorting, such as plastics, glass and ceramics.

A comparison of the thick-target model with stereo data on the height structure of solar hard x-ray bursts

Solar Physics ◽  
1983 ◽  
Vol 88 (1-2) ◽  
Author(s):  
J.C. Brown ◽  
V.A. Carlaw ◽  
D. Cromwell ◽  
S.R. Kane
Keyword(s):  
Thick Target ◽  
X Ray ◽  
Target Model ◽  
Stereo Data

scholarly journals PHEMTO: the polarimetric high energy modular telescope observatory

2021 ◽  
Author(s):  
P. Laurent ◽  
F. Acero ◽  
V. Beckmann ◽  
S. Brandt ◽  
F. Cangemi ◽  
...  
Keyword(s):  
Black Holes ◽  
Energy Range ◽  
High Performance ◽  
Angular Resolution ◽  
High Energy ◽  
Thermal Processes ◽  
Scientific Performance ◽  
X Ray ◽  
Measurement Capability ◽  
Better Than

AbstractBased upon dual focusing techniques, the Polarimetric High-Energy Modular Telescope Observatory (PHEMTO) is designed to have performance several orders of magnitude better than the present hard X-ray instruments, in the 1–600 keV energy range. This, together with its angular resolution of around one arcsecond, and its sensitive polarimetry measurement capability, will give PHEMTO the improvements in scientific performance needed for a mission in the 2050 era in order to study AGN, galactic black holes, neutrons stars, and supernovae. In addition, its high performance will enable the study of the non-thermal processes in galaxy clusters with an unprecedented accuracy.

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