Thermal electrons runaway from a hot plasma during a flare in the reverse-current model and their X-ray bremsstrahlung

Solar Physics ◽  
1988 ◽  
Vol 116 (1) ◽  
Author(s):  
S.V. Diakonov ◽  
B.V. Somov
Keyword(s):  
Current Model ◽  
Reverse Current ◽  
X Ray ◽  
Hot Plasma

REMARKS ON THE X-RAY CONTINUUM SPECTRUM EMITTED BY A HOT PLASMA

1987 ◽  
Vol 48 (C9) ◽  
pp. C9-383-C9-386
Author(s):  
C. MÖLLER ◽  
R. Y. YIN ◽  
M. LAMOUREUX
Keyword(s):  
X Ray ◽  
Continuum Spectrum ◽  
Hot Plasma

scholarly journals X-ray transmission grating spectrometer with CCD detector for laser plasma studies

1991 ◽  
Vol 9 (2) ◽  
pp. 579-591 ◽  
Author(s):  
L. Pína ◽  
H. Fiedorowicz ◽  
M. O. Koshevoi ◽  
A. A. Rupasov ◽  
B. Rus ◽  
...  
Keyword(s):  
Laser Plasma ◽  
Dynamic Range ◽  
High Sensitivity ◽  
Array Detector ◽  
Charge Coupled Device ◽  
X Ray ◽  
Transmission Grating ◽  
Hot Plasma ◽  
Ccd Detector ◽  
Wet Processing

A program is under way to develop methods and instrumentation based on charge-coupled device (CCD) sensors for hot plasma diagnostics. We have developed a new X-ray spectrometer in which a freestanding X-ray transmission grating is coupled to a CCD linear array detector with electronic digitized readout replacing film and its wet processing. This instrument measures time-integrated pulsed X-ray spectra with moderate spectral resolution (δλ ≤ 0.6 nm) over a broad spectral range (0.3–2 keV) with high sensitivity, linearity, and large dynamic range. The performance of the device was tested using laser plasma as the X-ray source.

scholarly journals SolpeX: the soft X-ray flare polarimeter–spectrometer for the ISS

2014 ◽  
Vol 10 (S305) ◽  
pp. 114-120
Author(s):  
Janusz Sylwester ◽  
Stefan Płocieniak ◽  
Jarosław Bakała ◽  
Żaneta Szaforz ◽  
Marek Stȩślicki ◽  
...  
Keyword(s):  
Solar Flares ◽  
Line Emission ◽  
Impulsive Phase ◽  
Particle Beams ◽  
X Ray ◽  
Hot Plasma ◽  
Spectral Imager ◽  
Polarized Bremsstrahlung ◽  
Made In ◽  
Fast Rotating

AbstractWe present the innovative soft X-ray spectro-polarimeter, SolpeX. This instrument consists of three functionally independent blocks. They are to be included into the Russian instrument KORTES, to be mounted onboard the ISS. The three SolpeX units are: a simple pin-hole X-ray spectral imager, a polarimeter, and a fast-rotating drum multiple-flat-crystal Bragg spectrometer. Such a combination of measuring blocks will offer a new opportunity to reliably measure possible X-ray polarization and spectra of solar flares, in particular during the impulsive phase. Polarized Bremsstrahlung and line emission due to the presence of directed particle beams will be detected, and measurements of the velocities of evaporated hot plasma will be made. In this paper we discuss the details of the construction of the SolpeX units. The delivery of KORTES with SolpeX to the ISS is expected to happen in 2017/2018.

Electron Acceleration in Collapsing Magnetic Traps during the Solar Flare on July 19, 2012: Observations and Models

2017 ◽  
Vol 13 (S335) ◽  
pp. 90-93
Author(s):  
P. A. Gritsyk ◽  
B. V. Somov
Keyword(s):  
Point Source ◽  
Solar Flares ◽  
High Efficiency ◽  
Reverse Current ◽  
Electron Acceleration ◽  
Thick Target ◽  
Two Dimensions ◽  
Magnetic Traps ◽  
Thin Target ◽  
X Ray

AbstractUsing the appropriate kinetic equation, we considered the problem of propagation of accelerated electrons into the solar corona and chromosphere. Its analytical solution was used for modelling the M7.7 class limb flare occurred on July 19, 2012. Coronal above-the-loop-top hard X-Ray source was interpreted in the thin-target approximation, the foot-point source - in the thick-target approximation with account of the reverse-current electric field. For the foot-point source we found a good accordance with the RHESSI observations. For the coronal source we also got very accurate estimate of the power-law spectral index, but significant differences between the modelled and observed hard X-ray intensities were noticed. The last discrepancy was solved by adding the coronal magnetic trap model to the thin target model. The former one implies that the trap collapses in two dimensions, locks and accelerates particles inside itself. In our report, we confirm an existence and high efficiency of the electron acceleration in collapsing magnetic traps during solar flares. Our new results represent (e.g. for RHESSI observations) the theoretical prediction of the double step particle acceleration in solar flares, when the first step is the acceleration in reconnection area and the second one – the acceleration in coronal trap.

Expansion of hot plasma with Kappa distribution in coronal flare sources

2021 ◽  
Author(s):  
Jan Benáček ◽  
Marian Karlický
Keyword(s):  
Langmuir Wave ◽  
Maxwellian Distribution ◽  
Double Layers ◽  
Kappa Distribution ◽  
One Dimensional ◽  
X Ray ◽  
Particle In Cell ◽  
Hot Plasma ◽  
The Difference ◽  
Field Lines

<p>We study how hot plasma that is released during a solar flare can be confined in its source and interact with surrounding colder plasma. The X-ray emission of coronal flare sources is well explained using Kappa velocity distribution. Therefore, we compare the difference in the confinement of plasma with Kappa and Maxwellian distribution. We use a 3D Particle-in-Cell code, which is large along magnetic field lines, effectively one-dimensional, but contains all electromagnetic effects. In the case with Kappa distribution, contrary to Maxwellian distribution, we found formation of several thermal fronts associated with double-layers that suppress particle fluxes. As the Kappa distribution of electrons forms an extended tail, more electrons are not confined by the first front and cause formation of multiple fronts. A beam of electrons from the hot part is formed at each front; it generates return current, Langmuir wave density depressions, and a double layer with a higher potential step than in the Maxwellian case. We compare the Kappa and Maxwellian cases and discuss how these processes could be observed.</p>

scholarly journals X-Ray Flares and Outflows Driven by Magnetic Interaction Between a Protostar and its Surrounding Disk

1997 ◽  
Vol 163 ◽  
pp. 717-718
Author(s):  
Mitsuru Hayashi ◽  
Kazunari Shibata ◽  
Ryoji Matsumoto
Keyword(s):  
Magnetic Field ◽  
Current Sheet ◽  
Plasma Temperature ◽  
Magnetic Interaction ◽  
Central Star ◽  
X Ray ◽  
Mhd Simulations ◽  
Flare Loops ◽  
Hot Plasma ◽  
Dipole Magnetic Field

AbstractHere we present a model of hard X-ray flares and hot plasma outflows (optical jets) observed in protostars. Assuming that the dipole magnetic field of a protostar threads the protostellar disk, we carried out 2.5-dimensional magnetohydrodynamic (MHD) simulations of the diskstar interaction. The closed magnetic loops connecting the central star and the disk are twisted by the rotation of the disk. In the presence of resistivity, magnetic reconnection takes place in the current sheet formed inside the expanding loops. Hot, outgoing plasmoid and post flare loops are formed as a result of the reconnection. Numerical results are consistent with the observed plasma temperature (107 – 108K), the length of the flaring loop (1011 – 1012cm), and the speed of optical jets (200 – 400 km s−1 ).

scholarly journals The Nature of the Compact Object in the Hard X-Ray Source 4U2206+54

2004 ◽  
Vol 194 ◽  
pp. 208-208
Author(s):  
J. M. Torrejón ◽  
I. Kreykenbohni ◽  
A. Orr ◽  
L. Titarchuk ◽  
I. Negueruela
Keyword(s):  
Neutron Star ◽  
Accretion Disk ◽  
Compact Object ◽  
High Energy ◽  
Energy Data ◽  
X Ray ◽  
Hot Plasma ◽  
Cyclotron Line ◽  
First Time

We present an analysis of archival RXTE and BeppoSAX data of the X-ray source 4U2206+54. For the first time, high energy data (≥ 30 keV) is analyzed. The data is well described by comptonization models in which seed photons with temperatures between 1.1 keV arid 1.5 keV are comptonized by a hot plasma at 50 keV thereby producing a hard tail which extends up to 100 keV. From luminosity arguments it is shown that the area of the soft photons source must be small (r ≈ 1 km) and that the presence of an accretion disk in this system is unlikely. Here we report on the possible existence of a cyclotron line around 30 keV . The presence of a neutron star in the system is strongly favored by the available data.

Mixed-morphology supernova remnants: the case of SNR 0520–69.4 in the Large Magellanic Cloud

2020 ◽  
Vol 499 (3) ◽  
pp. 4213-4222
Author(s):  
I Ramírez-Ballinas ◽  
J Reyes-Iturbide ◽  
P Ambrocio-Cruz ◽  
R Gabbasov ◽  
M Rosado
Keyword(s):  
Supernova Remnants ◽  
Plasma Temperature ◽  
Optical Emission ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Physical Parameters ◽  
X Ray ◽  
Hot Plasma ◽  
Observatory Data ◽  
Fabry Perot

ABSTRACT We present observations in X-ray and optical emission of the supernova remnant (SNR) 0520–69.4 in the Large Magellanic Cloud. Using XMM–Newton observatory data, we produced images of the diffuse X-ray emission and spectra to obtain the X-ray parameters, such as luminosity and temperature, of hot plasma in the SNR. Diffuse X-ray emission with filled-centre morphology goes beyond the Hα region, suggesting that the hot gas escapes through the pores of the Hα shell. We fitted a model that has a plasma temperature of 1.1 × 107 K for an X-ray thermal luminosity of 3.3 × 1035 erg s−1. However, from Hα and [O iii] Fabry–Perot observations obtained with the Marseille Hα Survey of the Magellanic Clouds and the Milky Way at La Silla, European Southern Observatory, we are able to obtain physical parameters such as the velocity of the shock induced in the cloudlets emitting at optical wavelengths and the electron density of this gas. With the parameters described above, we test the model proposed by White & Long (1991, ApJ, 373, 543) for explaining the mixed-morphology observed.

scholarly journals X-ray Emission from Hot DA White Dwarfs; EXOSAT Results, and Implications for Atmospheric Models

1989 ◽  
Vol 114 ◽  
pp. 198-201
Author(s):  
Frits Paerels ◽  
John Heise
Keyword(s):  
Systematic Uncertainty ◽  
Effective Temperature ◽  
White Dwarfs ◽  
Current Model ◽  
Broad Band ◽  
Model Calculations ◽  
X Ray ◽  
Transmission Grating ◽  
Upper Limit ◽  
Optical Flux

AbstractWe present the observations of the photospheric X-ray spectra of hot DA white dwarfs, obtained with the 500 lines mm−1 Transmission Grating Spectrometer on EXOSAT. These spectra cover the full soft X-ray band, at high wavelength resolution and statistical quality. They allow us to do an accurate measurement of the photospheric parameters, particularly of effective temperature and chemical composition of the atmosphere.We consider the case of HZ 43 in some detail. Model atmospheric spectra that satisfy all measured absolute optical, UV and X-ray fluxes turn out not to fit the shape of the measured X-ray spectrum. However, from a comparison of model spectra calculated with different model atmospheres codes we infer the existence of a 15% systematic uncertainty in the model fluxes at the shortest wavelengths (λ < 100 Å) in current model calculations. This can explain the fitting problem. Since the systematic uncertainty in the models is larger than the statistical uncertainty in the shape of the measured X-ray spectrum of HZ 43, we cannot at present use this measured shape to derive the effective temperature and gravity. We revert to broad band photometry, using the measured integrated soft X-ray flux and the optical flux, to determine Te = 45,000 – 54,000K, R/R⊙ = 0.0140 – 0.0165. From the absence of the He II Ly edge at 227 Å in the measured spectrum, we set a upper limit on the photospheric helium abundance of He/H = 1.0 × 10−5; this upper limit is independent of the uncertainties in the model calculations mentioned above.

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