scholarly journals Two-temperature magnetohydrodynamic simulations for sub-relativistic active galactic nucleus jets: dependence on the fraction of the electron heating

2020 ◽  
Vol 493 (4) ◽  
pp. 5761-5772 ◽  
Author(s):  
Takumi Ohmura ◽  
Mami Machida ◽  
Kenji Nakamura ◽  
Yuki Kudoh ◽  
Ryoji Matsumoto
Keyword(s):  
Electron Temperature ◽  
X Rays ◽  
Ion Temperature ◽  
Temperature Plasma ◽  
Electron Heating ◽  
Coulomb Collisions ◽  
X Ray ◽  
Jet Plasma ◽  
Magnetohydrodynamic Simulations ◽  
Two Temperature

ABSTRACT We present the results of two-temperature magnetohydrodynamic simulations of the propagation of sub-relativistic jets of active galactic nuclei. The dependence of the electron and ion temperature distributions on the fraction of electron heating, fe, at the shock front is studied for fe = 0, 0.05, and 0.2. Numerical results indicate that in sub-relativistic, rarefied jets, the jet plasma crossing the terminal shock forms a hot, two-temperature plasma in which the ion temperature is higher than the electron temperature. The two-temperature plasma expands and forms a backflow referred to as a cocoon, in which the ion temperature remains higher than the electron temperature for longer than 100 Myr. Electrons in the cocoon are continuously heated by ions through Coulomb collisions, and the electron temperature thus remains at Te > 109 K in the cocoon. X-ray emissions from the cocoon are weak because the electron number density is low. Meanwhile, X-rays are emitted from the shocked intracluster medium (ICM) surrounding the cocoon. Mixing of the jet plasma and the shocked ICM through the Kelvin–Helmholtz instability at the interface enhances X-ray emissions around the contact discontinuity between the cocoon and shocked ICM.

scholarly journals Two-Temperature Magnetohydrodynamics Simulations of Propagation of Semi-Relativistic Jets

Galaxies ◽  
2019 ◽  
Vol 7 (1) ◽  
pp. 14 ◽  
Author(s):  
Takumi Ohmura ◽  
Mami Machida ◽  
Kenji Nakamura ◽  
Yuki Kudoh ◽  
Yuta Asahina ◽  
...  
Keyword(s):  
Electron Temperature ◽  
Galactic Nuclei ◽  
Thermal Dissipation ◽  
Coulomb Collision ◽  
Astrophysical Jets ◽  
Ion Temperature ◽  
Bremsstrahlung Radiation ◽  
Coulomb Collisions ◽  
The Difference ◽  
Two Temperature

In astrophysical jets observed in active galactic nuclei and in microquasars, the energy exchange rate by Coulomb collision is insufficient for thermal equilibrium between ions and electrons. Therefore, it is necessary to consider the difference between the ion temperature and the electron temperature. We present the results of two-temperature magnetohydrodynamics(MHD) simulations to demonstrate the effects of Coulomb coupling. It is assumed that the thermal dissipation heats only ions. We find that the ion and electron temperatures are separated through shocks. Since the ion entropy is increased by energy dissipation at shocks and the Coulomb collisions are inefficient, electron temperature becomes about 10 times lower than the ion temperature in the hotspot ahead of the jet terminal shock. In the cocoon, electron temperature decreases by gas mixing between high temperature cocoon gas and low temperature shocked-ambient gas even when we neglect radiative cooling, but electrons can be heated through collisions with ions. Radiation intensity maps are produced by post processing numerical results. Distributions of the thermal bremsstrahlung radiation computed from electron temperature have bright filament and cavity around the jet terminal shock.

scholarly journals X-ray evidence for wind-wind collision in the Wolf-Rayet binary V444 Cygni

1999 ◽  
Vol 193 ◽  
pp. 398-399
Author(s):  
Jun Yokogawa ◽  
Katsuji Koyama ◽  
Yoshitomo Maeda ◽  
Steve L. Skinner
Keyword(s):  
Soft Component ◽  
X Rays ◽  
Plasma Model ◽  
Temperature Plasma ◽  
Absorption Column ◽  
Hard Component ◽  
Eclipsing Binary ◽  
X Ray ◽  
The Individual ◽  
Two Temperature

We present results on the eclipsing binary V444 Cyg (WN5+O6) with the X-ray satellite ASCA. The observations were performed at orbital phases 0.0, 0.25 and 0.5 (the 06 star is in front at phase 0.5 and vice versa at phase 0.0). Two-temperature plasma model could reproduce X-ray spectra in each phase. The temperature of the soft component is lower (kT ≃ 0.6 keV), which is attributed to the individual O6/WN5 stars. The temperature of the hard component is higher (kT ≃ 2 keV), which exhibited phase-related time-variabilities in absorption column NH and luminosity LX; NH was maximal at phase 0.0 while LX was minimal at phase 0.5. These variabilities are consistent with the scenario that X-rays are emitted from plasma heated-up by wind-wind collision near the surface of the O6 star.

scholarly journals X-ray evolution of the nova V959 Mon suggests a delayed ejection and a non-radiative shock

2020 ◽  
Vol 500 (3) ◽  
pp. 2798-2812
Author(s):  
Thomas Nelson ◽  
Koji Mukai ◽  
Laura Chomiuk ◽  
Jennifer L Sokoloski ◽  
Justin D Linford ◽  
...  
Keyword(s):  
Gamma Rays ◽  
Column Density ◽  
X Rays ◽  
Radio Observations ◽  
Reverse Shock ◽  
Temperature Plasma ◽  
Radiative Shock ◽  
X Ray ◽  
Solar Abundances ◽  
Two Temperature

ABSTRACT X-ray observations of shocked gas in novae can provide a useful probe of the dynamics of the ejecta. Here we report on X-ray observations of the nova V959 Mon, which was also detected in GeV gamma-rays with the Fermi satellite. We find that the X-ray spectra are consistent with a two-temperature plasma model with non-solar abundances. We interpret the X-rays as due to shock interaction between the slow equatorial torus and the fast polar outflow that were inferred from radio observations of V959 Mon. We further propose that the hotter component, responsible for most of the flux, is from the reverse shock driven into the fast outflow. We find a systematic drop in the column density of the absorber between days 60 and 140, consistent with the expectations for such a picture. We present intriguing evidence for a delay of around 40 d in the expulsion of the ejecta from the central binary. Moreover, we infer a relatively small (a few times 10−6 M⊙) ejecta mass ahead of the shock, considerably lower than the mass of 104 K gas inferred from radio observations. Finally, we infer that the dominant X-ray shock was likely not radiative at the time of our observations, and that the shock power was considerably higher than the observed X-ray luminosity. It is unclear why high X-ray luminosity, closer to the inferred shock power, is never seen in novae at early times, when the shock is expected to have high enough density to be radiative.

scholarly journals New Approach, Taking into Account Elastic and Inelastic Processes, for Transport Properties of a two Temperature Plasma

1985 ◽  
Vol 40 (9) ◽  
pp. 885-891 ◽  
Author(s):  
C. Bonnefoi ◽  
J. Aubreton ◽  
J.-M. Mexmain
Keyword(s):  
Thermal Conductivity ◽  
Electron Temperature ◽  
Plasma Electron ◽  
Temperature Plasma ◽  
Heavy Particles ◽  
New Approach ◽  
Definition Of ◽  
Thermal Conductivity Λ ◽  
Two Temperature ◽  
Inelastic Processes

Abstract We have developed a modified Chapman-Enskog method for a two-temperature partially ionized plasma: electron temperature (Te) and heavy particles temperature (Th). We introduce a new definition of the diffusion forces and then calculate the reactive thermal conductivity λR.

scholarly journals A unified accretion-ejection paradigm for black hole X-ray binaries

2019 ◽  
Vol 626 ◽  
pp. A115 ◽  
Author(s):  
G. Marcel ◽  
J. Ferreira ◽  
M. Clavel ◽  
P.-O. Petrucci ◽  
J. Malzac ◽  
...  
Keyword(s):  
Radio Emission ◽  
Accretion Disk ◽  
Ad Hoc ◽  
Emission Model ◽  
X Rays ◽  
Temperature Plasma ◽  
X Ray ◽  
Fitting Procedure ◽  
High Level ◽  
X Ray Binaries

Context. Transient X-ray binaries (XrB) exhibit very different spectral shapes during their evolution. In luminosity-color diagrams, their behavior in X-rays forms q-shaped cycles that remain unexplained. In Paper I, we proposed a framework where the innermost regions of the accretion disk evolve as a response to variations imposed in the outer regions. These variations lead not only to modifications of the inner disk accretion rate ṁin, but also to the evolution of the transition radius rJ between two disk regions. The outermost region is a standard accretion disk (SAD), whereas the innermost region is a jet-emitting disk (JED) where all the disk angular momentum is carried away vertically by two self-confined jets. Aims. In the previous papers of this series, it has been shown that such a JED–SAD disk configuration could reproduce the typical spectral (radio and X-rays) properties of the five canonical XrB states. The aim of this paper is now to replicate all X-ray spectra and radio emission observed during the 2010–2011 outburst of the archetypal object GX 339-4. Methods. We used the two-temperature plasma code presented in two previous papers (Papers II and III) and designed an automatic ad hoc fitting procedure that for any given date calculates the required disk parameters (ṁin,rJ) that fit the observed X-ray spectrum best. We used X-ray data in the 3–40 keV (RXTE/PCA) spread over 438 days of the outburst, together with 35 radio observations at 9 GHz (ATCA) dispersed within the same cycle. Results. We obtain the time distributions of ṁin(t) and rJ(t) that uniquely reproduce the X-ray luminosity and the spectral shape of the whole cycle. In the classical self-absorbed jet synchrotron emission model, the JED–SAD configuration also reproduces the radio properties very satisfactorily, in particular, the switch-off and -on events and the radio-X-ray correlation. Although the model is simplistic and some parts of the evolution still need to be refined, this is to our knowledge the first time that an outburst cycle is reproduced with such a high level of detail. Conclusions. Within the JED–SAD framework, radio and X-rays are so intimately linked that radio emission can be used to constrain the underlying disk configuration, in particular, during faint hard states. If this result is confirmed using other outbursts from GX 339-4 or other X-ray binaries, then radio could be indeed used as another means to indirectly probe disk physics.

X-Ray Emission from High-Temperature Laboratory, Plasmas

1974 ◽  
Vol 18 ◽  
pp. 1-25
Author(s):  
D. J. Nagel
Keyword(s):  
Power Generation ◽  
High Temperature ◽  
Diagnostic Information ◽  
X Rays ◽  
Temperature Plasma ◽  
Fusion Power ◽  
X Ray ◽  
High Temperature Plasma ◽  
Laboratory Plasmas

AbstractThe radiation from plasmas hotter than 106K falls in the x-ray region. Such plasmas are required for fusion power generation. They can also be used as x-ray sources. Measurements of x-ray emission from high temperature plasma yields (a) diagnostic information on the plasma conditions and (b) the characteristics of plasma x-ray sources which determine their applications. Hence, measurements of x-rays from plasmas are finding widespread use.

scholarly journals The effect of electron bite-outs on artificial electron heating and the PMSE overshoot

2005 ◽  
Vol 23 (12) ◽  
pp. 3633-3643 ◽  
Author(s):  
M. Kassa ◽  
O. Havnes ◽  
E. Belova
Keyword(s):  
Electron Temperature ◽  
Electron Density ◽  
Electron Density Profile ◽  
Dust Particles ◽  
High Electron ◽  
Heating Effect ◽  
Ion Temperature ◽  
Degree Of Ionization ◽  
Electron Heating ◽  
Transmitter Power

Abstract. We have considered the effect that a local reduction in the electron density (an electron bite-out), caused by electron absorption on to dust particles, can have on the artificial electron heating in the height region between 80 to 90km, where noctilucent clouds (NLC) and the radar phenomenon PMSE (Polar Mesospheric Summer Echoes) are observed. With an electron density profile without bite-outs, the heated electron temperature Te,hot will generally decrease smoothly with height in the PMSE region or there may be no significant heating effect present. Within a bite-out Te,hot will decrease less rapidly and can even increase slightly with height if the bite-out is strong. We have looked at recent observations of PMSE which are affected by artificial electron heating, with a heater cycling producing the new overshoot effect. According to the theory for the PMSE overshoot the fractional increase in electron temperature Te,hot/Ti, where Ti is the unaffected ion temperature=neutral temperature, can be found from the reduction in PMSE intensity as the heater is switched on. We have looked at results from four days of observations with the EISCAT VHF radar (224 MHz), together with the EISCAT heating facility. We find support for the PMSE overshoot and heating model from a sequence of observations during one of the days where the heater transmitter power is varied from cycle to cycle and where the calculated Te,hot/Ti is found to vary in proportion to the transmitter power. We also looked for signatures of electron bite-outs by examining the variation of Te,hot/Ti with height for the three other days. We find that the height variation of Te,hot/Ti is very different on the three days. On one of the days we see typically that this ratio can increase with height, showing the presence of a bite-out, while on the next day the heating factor mainly decreases with height, indicating that the fractional amount of dust is low, so that the electron density is hardly affected by it. On the third day there is little heating effect on the PMSE layer. This is probably due to a sufficiently high electron density in the atmosphere below the PMSE layer, so that the transmitted heater power is absorbed in these lower layers. On this day the D-region, as given by the UHF (933MHz) observations, extends deeper down in the atmosphere than on the other two days, indicating that the degree of ionization in and below the PMSE layers is higher as well.

scholarly journals Characterization of laser-driven electron and photon beams using the Monte Carlo code FLUKA

2014 ◽  
Vol 32 (2) ◽  
pp. 233-241 ◽  
Author(s):  
F. Fiorini ◽  
D. Neely ◽  
R.J. Clarke ◽  
S. Green
Keyword(s):  
Monte Carlo ◽  
Electron Temperature ◽  
Spectral Characteristics ◽  
Simulation Method ◽  
Target Thickness ◽  
Monte Carlo Code ◽  
X Rays ◽  
Photon Beams ◽  
X Ray ◽  
Plasma Effects

AbstractWe present a new simulation method to predict the maximum possible yield of X-rays produced by electron beams accelerated by petawatt lasers irradiating thick solid targets. The novelty of the method lies in the simulation of the electron refiluxing inside the target implemented with the Monte Carlo code Fluka. The mechanism uses initial theoretical electron spectra, cold targets and refiluxing electrons forced to re-enter the target iteratively. Collective beam plasma effects are not implemented in the simulation. Considering the maximum X-ray yield obtained for a given target thickness and material, the relationship between the irradiated target mass thickness and the initial electron temperature is determined, as well as the effect of the refiluxing on X-ray yield. The presented study helps to understand which electron temperature should be produced in order to generate a particular X-ray beam. Several applications, including medical and security imaging, could benefit from laser generated X-ray beams, so an understanding of the material and the thickness maximizing the yields or producing particular spectral characteristics is necessary. On the other more immediate hand, if this study is experimentally reproduced at the beginning of an experiment in which there is an interest in laser-driven electron and/or photon beams, it can be used to check that the electron temperature is as expected according to the laser parameters.

X-Ray Absroption Table for the 2-to-200 Å Region

1969 ◽  
Vol 13 ◽  
pp. 639-665 ◽  
Author(s):  
B. L, Henke and ◽  
R. L. Elgin
Keyword(s):  
Extreme Ultraviolet ◽  
Bragg Reflection ◽  
Pulse Height ◽  
X Rays ◽  
Temperature Plasma ◽  
X Ray ◽  
Langmuir Blodgett ◽  
Intensity Measurements ◽  
Measured Absorption ◽  
Physical And Chemical

Physical and chemical analysis, X-ray astronomy and high temperature plasma diagnostics which utilize the ultrasoft X-radiations hare made evident a strong need for filling the gap in measured absorption coefficient data for the radiations between the conventional X-rays and the extreme ultraviolet. More than one hundred new coefficients have been measured in this laboratory on the gas state, atomic or molecular, containing He, C, N, 0, F, Ne, S, Cl, Ar, Kr and Xe using eleven fluorescent, characteristic wavelengths Al-Kα (8.34 A) through Be-K (113.8 A). The radiations were isolated by Bragg reflection from multilayer analyzers of the Langmuir-Blodgett type and by pulse height discriminating proportional counter intensity measurements.

scholarly journals Thermal and Non-Thermal X-Rays from SN 1006 and IC 443

1998 ◽  
Vol 188 ◽  
pp. 256-257
Author(s):  
M. Ozaki ◽  
K. Koyama
Keyword(s):  
High Temperature ◽  
Supernova Remnants ◽  
Recent Observation ◽  
X Rays ◽  
Temperature Plasma ◽  
Hard Component ◽  
X Ray ◽  
High Temperature Plasma ◽  
Thermal Origin ◽  
Non Equilibrium

From many Galactic supernova remnants (SNRs), X-ray emissions consisting of non-equilibrium ionization (NEI) plasma and additional hard component are detected. The hard emission have been usually interpreted as a high temperature plasma of = 10 keV. However, the recent observation with ASCA made it clear that the hard components of some SNRs are of non-thermal origin. Here we report the ASCA results of SN 1006 and IC 443 observations as an example of such SNRs.

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