scholarly journals Two‐dimensional Magnetohydrodynamic Numerical Simulations of Magnetic Reconnection Triggered by a Supernova Shock in the Interstellar Medium: Generation of X‐Ray Gas in the Galaxy

2001 ◽  
Vol 551 (1) ◽  
pp. 312-332 ◽  
Author(s):  
Syuniti Tanuma ◽  
Takaaki Yokoyama ◽  
Takahiro Kudoh ◽  
Kazunari Shibata
Keyword(s):  
Interstellar Medium ◽  
Numerical Simulations ◽  
Magnetic Reconnection ◽  
Two Dimensional ◽  
X Ray ◽  
The Galaxy

scholarly journals MHD Numerical Simulations of Magnetic Reconnection Associated with Emerging Flux

1993 ◽  
Vol 141 ◽  
pp. 500-503
Author(s):  
K. Shibata ◽  
S. Nozawa ◽  
R. Matsumoto
Keyword(s):  
Magnetic Field ◽  
Numerical Simulations ◽  
Magnetic Reconnection ◽  
Coronal Magnetic Field ◽  
Two Dimensional ◽  
Magnetic Islands ◽  
X Ray ◽  
Hot Plasma ◽  
Mass Ejection ◽  
Coronal Field

AbstractTwo-dimensional (2D) magnetohydrodynamic (MHD) numerical simulations have been performed to study magnetic reconnection between emerging flux and the overlying coronal magnetic field, taking into account of gravity. It is found that (1) reconnection starts when most of chromospheric mass in the current sheet between the emerging flux and the coronal field has drained down along the loop because of gravity, (2) multiple magnetic islands, which confine cool, dense chromospheric plasma, are created in the sheet; the islands coalesce dynamically and are ejected along the sheet, together with the ambient hot plasma, at Alfven speed. The coexistence of hot and cool plasmas in the mass ejection (jet) associated with the reconnection seems to explain those X-ray jets observed by Yohkoh, which are identified with Hα surges.

scholarly journals Astrophysical MHD turbulence: confluence of observations, simulations, and theory

2012 ◽  
Vol 8 (S294) ◽  
pp. 325-336 ◽  
Author(s):  
Blakesley Burkhart ◽  
Alex Lazarian
Keyword(s):  
Star Formation ◽  
Interstellar Medium ◽  
Magnetic Reconnection ◽  
Particle Transport ◽  
Recent Progress ◽  
Critical Component ◽  
Dynamo Theory ◽  
Mhd Turbulence ◽  
The Galaxy

AbstractMagnetohydrodynamic (MHD) turbulence is a critical component of the current paradigms of star formation, dynamo theory, particle transport, magnetic reconnection and evolution of the ISM. In order to gain understanding of how MHD turbulence regulates processes in the Galaxy, a confluence of numerics, observations and theory must be imployed. In these proceedings we review recent progress that has been made on the connections between theoretical, numerical, and observational understanding of MHD turbulence as it applies to both the neutral and ionized interstellar medium.

scholarly journals Quasi-separatrix Layers Induced by Ballooning Instability in Near-Earth Magnetotail

2019 ◽  
Author(s):  
Ping Zhu ◽  
Zechen Wang ◽  
Jun Chen ◽  
Xingting Yan ◽  
Rui Liu
Keyword(s):  
Numerical Simulations ◽  
Magnetic Reconnection ◽  
Solar Physics ◽  
Close Correlation ◽  
Satellite Observations ◽  
Two Dimensional ◽  
3 Dimensional ◽  
Ballooning Instability ◽  
3D Geometry ◽  
Alternative Means

Abstract. Magnetic reconnection processes in the near-Earth magnetotail can be highly 3-dimensional (3D) in geometry and dynamics, even though the magnetotail configuration itself is nearly two dimensional due to the symmetry in the dusk-dawn direction. Such reconnection processes can be induced by the 3D dynamics of nonlinear ballooning instability. In this work, we explore the global 3D geometry of the reconnection process induced by ballooning instability in the near-Earth magnetotail by examining the distribution of quasi-separatrix layers associated with plasmoid formation in the entire 3D domain of magnetotail configuration, using an algorithm previously developed in context of solar physics. The 3D distribution of quasi-separatrix layers (QSLs) as well as their evolution directly follows the plasmoid formation during the nonlinear development of ballooning instability in both time and space. Such a close correlation demonstrates a strong coupling between the ballooning and the corresponding reconnection processes. It further confirms the intrinsic 3D nature of the ballooning-induced plasmoid formation and reconnection processes, in both geometry and dynamics. In addition, the reconstruction of the 3D QSL geometry may provide an alternative means for identifying the location and timing of 3D reconnection sites in magnetotail from both numerical simulations and satellite observations.

scholarly journals The O stars: optical review

1979 ◽  
Vol 83 ◽  
pp. 1-22
Author(s):  
J. B. Hutchings
Keyword(s):  
Neutron Star ◽  
Interstellar Medium ◽  
Mass Loss ◽  
Large Fraction ◽  
Significant Fraction ◽  
High Mass ◽  
X Ray ◽  
The Galaxy ◽  
High Mass Loss ◽  
Rough Outline

I would like to start with a quick overview of the O stars - their significance and role in the galaxy and in astrophysics - just to remind ourselves of why we are here and what we hope to talk about. In Table 1 I show a rough outline of the contribution of O stars to what happens in the galaxy as a whole. Because of their extreme luminosity, they contribute a large fraction of the radiation of the galaxy, while forming a very tiny group of objects and mass. Because of their short lifetime they are a population that has gone through 104 generations in the life of the galaxy. Their high mass loss rates may account for a large fraction of the new matter injected into the interstellar medium, and they probably power some significant fraction of the hard X-ray sources in the galaxy, by virtue of the fact that a companion can become a neutron star a) without disrupting the binary and b) while the companion is still a mass losing O star.

scholarly journals X-Ray Superbubbles

1983 ◽  
Vol 6 ◽  
pp. 675-680
Author(s):  
Webster Cash
Keyword(s):  
Interstellar Medium ◽  
Collective Effects ◽  
Selection Effects ◽  
X Rays ◽  
High Quality ◽  
X Ray ◽  
Common Structure ◽  
The Galaxy ◽  
Gum Nebula

AbstractFour regions of the galaxy, the Cygnus Superbubble, the ƞ Carina complex, the Orion/Eridanus complex, and the Gum Nebula, are discussed as examples of collective effects in the interstellar medium. All four regions share certain features, indicating a common structure. We discuss the selection effects which determine the observable x-ray properties of the superbubbles and demonstrate that only a very few more in our galaxy can be detected in x-rays. X-ray observation of extragalactic superbubbles is shown to be possible but requires the capabilities of a large, high quality, AXAF class observatory.

Effects of Materials on Formation of Double-Layered Liners Shaped Charges

2009 ◽  
Vol 79-82 ◽  
pp. 1277-1280
Author(s):  
Yu Zheng ◽  
Xiao Ming Wang ◽  
Wen Bin Li ◽  
Wen Jin Yao
Keyword(s):  
Numerical Simulation ◽  
Finite Element ◽  
Numerical Simulations ◽  
Double Layer ◽  
Two Dimensional ◽  
Materials Properties ◽  
X Ray ◽  
Dimensional Finite Element ◽  
Simulation Results ◽  
Good Agreement

In order to study the effects of liner materials on the formation of Shaped Charges with Double Layer Liners (SCDLL) into tandem Explosively Formed Projectile (EFP), the formation mechanism of DLSCL was studied. Utilizing two-dimensional finite element dynamic code AUTODYN, the numerical simulations on the mechanical phenomenon of SCDLL forming into tandem EFP were carried out. X-ray pictures were obtained after Experiments on SCDLL. Comparisons between experimental results and numerical simulation results have good agreement. It can be concluded from the results that the materials properties and configurations of both liners are crucial to the formation of tandem EFP.

GRB-SN CONNECTION: CENTRAL ENGINE OF LONG GRBs AND EXPLOSIVE NUCLEOSYNTHESIS

2011 ◽  
Vol 20 (10) ◽  
pp. 1975-1978 ◽  
Author(s):  
SHIGEHIRO NAGATAKI
Keyword(s):  
Numerical Simulations ◽  
Deposition Rate ◽  
Energy Deposition ◽  
Two Dimensional ◽  
Hydrodynamic Simulations ◽  
X Ray ◽  
Central Engine ◽  
Explosive Nucleosynthesis ◽  
General Relativistic ◽  
Energy Deposition Rate

I have developed two-dimensional general relativistic magnetohydrodynamic (GRMHD) code. I have performed numerical simulations of collapsars using these codes and realistic progenitor models. In the GRMHD simulation, it is shown that a jet is launched from the center of the progenitor. We also performed two-dimensional hydrodynamic simulations in the context of collapsar model to investigate the explosive nucleosynthesis happened there. It is found that the amount of 56 Ni is very sensitive to the energy deposition rate. This result means that the amount of synthesized 56 Ni can be little even if the total explosion energy is as large as 1052 erg. Thus, some GRBs can associate with faint supernovae. Thus we consider it is quite natural to detect no underlying supernova in some X-ray afterglows.

scholarly journals Feedback in the Dark Domain

2009 ◽  
Vol 5 (S267) ◽  
pp. 362-369
Author(s):  
Keiichi Wada
Keyword(s):  
Black Hole ◽  
High Resolution ◽  
Interstellar Medium ◽  
Numerical Simulations ◽  
Dynamical Effect ◽  
Theoretical Knowledge ◽  
X Ray ◽  
Supermassive Black Hole

AbstractIn order to clarify the physics of AGN feedback and feeding, we need to understand the interstellar medium (ISM) in the central several tens of parsecs in galaxies where our observational and theoretical knowledge is relatively poor. Here we discuss feedback processes due to strong far UV and X-ray radiation, as well as the dynamical effect of a supermassive black hole (SMBH) based on new high-resolution numerical simulations of the ISM in the central R ≤ 32 pc region around a SMBH at the center of a galaxy.

scholarly journals Evolution of the Coronae in Early-Type Galaxies

1990 ◽  
Vol 115 ◽  
pp. 240-244
Author(s):  
L.P. David ◽  
W. Forman ◽  
C. Jones
Keyword(s):  
Mass Loss ◽  
Numerical Simulations ◽  
Elliptical Galaxies ◽  
Compact Groups ◽  
Type I ◽  
Dark Halo ◽  
Early Type ◽  
X Ray ◽  
Galactic Winds ◽  
The Galaxy

AbstractWe present numerical simulations of the gaseous coronae in elliptical galaxies. These models consist of a modified King profile for the luminous portion of the galaxy and an isothermal dark halo. We include evolving stellar mass loss from planetary nebulae, and type I and II supernovae. Our models show that elliptical galaxies are likely to produce strong galactic winds at early times with x-ray luminosities of 1042 — 1044 ergs s-1 and temperatures of 10 keV. Galaxies can lose approximately 10-30% of their initial luminous mass in the wind which has an oxygen-to-iron ratio twice the solar value. Since elliptical galaxies are a principle component of rich clusters and compact groups this early wind phase affects the metallicity and temperature of the intracluster medium.

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