scholarly journals Solution of Flow Problems in Unidimensional Lagrangian Hydromagnetics

1957 ◽  
Vol 10 (1) ◽  
pp. 213 ◽  
Author(s):  
RE Loughhead
Keyword(s):  
Magnetic Fields ◽  
Initial Time ◽  
High Current ◽  
Ionized Gas ◽  
Flow Problems ◽  
Solar Prominences ◽  
High Current Discharge ◽  
Infinite Extent ◽  
The Galaxy ◽  
A Current

A problem of considerable interest in many branches of astrophysics is that of the subsequent behaviour of a current which at an initial time t = 0 is largely concentrated within a given region of an ionized gas of infinite extent. In particular, it has been suggested by Alfv�n (1950) that a high current discharge in an ionized gas is likely to constrict because of the electromagnetic attraction' between parallel currents and that this constriction effect may be involved in the formation of solar prominences. Similar considerations may also be of importance in studies of magnetic fields in the spiral arms of the Galaxy.

Pulsed high-current discharge in water: adiabatic model of expanding plasma channel and acoustic wave

2021 ◽  
Author(s):  
Andrey V. Kozyrev ◽  
Andrey A. Zherlitsyn ◽  
Natalia S. Semeniuk
Keyword(s):  
Acoustic Wave ◽  
Pulsed Power ◽  
High Current ◽  
Number Density ◽  
Pulsed Discharge ◽  
Current Channel ◽  
High Current Discharge ◽  
Isothermal Plasma ◽  
A Current ◽  
Good Agreement

Abstract This paper presents the results of a theoretical and experimental study of the use of a pulsed discharge in water to obtain a strong acoustic wave in a liquid medium. A discharge with a current amplitude of 10 kA, a duration of 400 ns, and an amplitude pulsed power of 280 MW in water at atmospheric pressure created an expanding acoustic wave with an amplitude of more than 100 MPa. To describe the formation of the discharge channel, an isothermal plasma model has been developed, which made it possible to calculate both the expansion dynamics of a high-current channel and the strong acoustic wave generated by it. Our calculations show that the number density of plasma in the channel reaches 10^20 cm^(–3), while the degree of water vapour ionization is about 10%, and the channel wall extends with a velocity of 500 m/s. The calculations for the acoustic wave are in good agreement with measurements

scholarly journals Formation of plasma jets by a high-current discharge in metal vapor

2021 ◽  
Vol 2064 (1) ◽  
pp. 012033
Author(s):  
V A Kokshenev ◽  
N E Kurmaev
Keyword(s):  
Transmission Line ◽  
Metal Vapor ◽  
Plasma Jets ◽  
Aluminum Electrode ◽  
Marx Generator ◽  
Ceramic Surface ◽  
High Current ◽  
Plasma Sources ◽  
High Current Discharge ◽  
A Current

Abstract Plasma sources based on high-current discharges (up to 20 kA) in vapors of an aluminum electrode material with initiation over the ceramic surface are investigated. Plasma flows with a divergence angle ≤ 20° and a pulse pressure of ~ 106 Pa were obtained. A design of a crowbar spark gap based on a plasma switch with developed plasma sources built into a magnetically insulated transmission line has been proposed and tested. A crowbar mode is implemented in the transmission line with a current of a mega-ampere level with a cut-off of the load circuit from the megajoule generator GIT-12 for the period of discharge of the Marx generator.

scholarly journals The Origin and Dynamical Effects of the Magnetic Fields and Cosmic Rays in the Disk of the Galaxy

1970 ◽  
Vol 39 ◽  
pp. 168-183
Author(s):  
E. N. Parker
Keyword(s):  
Magnetic Field ◽  
Cosmic Rays ◽  
Magnetic Fields ◽  
Dynamical Behavior ◽  
Cosmic Ray ◽  
Interested Reader ◽  
Written Text ◽  
The Galaxy ◽  
Basic Ideas ◽  
The Magnetic Field

The topic of this presentation is the origin and dynamical behavior of the magnetic field and cosmic-ray gas in the disk of the Galaxy. In the space available I can do no more than mention the ideas that have been developed, with but little explanation and discussion. To make up for this inadequacy I have tried to give a complete list of references in the written text, so that the interested reader can pursue the points in depth (in particular see the review articles Parker, 1968a, 1969a, 1970). My purpose here is twofold, to outline for you the calculations and ideas that have developed thus far, and to indicate the uncertainties that remain. The basic ideas are sound, I think, but, when we come to the details, there are so many theoretical alternatives that need yet to be explored and so much that is not yet made clear by observations.

scholarly journals Survival of molecular gas in a stellar feedback-driven outflow witnessed with the MUSE TIMER project and ALMA

2019 ◽  
Vol 488 (3) ◽  
pp. 3904-3928 ◽  
Author(s):  
Ryan Leaman ◽  
Francesca Fragkoudi ◽  
Miguel Querejeta ◽  
Gigi Y C Leung ◽  
Dimitri A Gadotti ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Star Formation ◽  
Mechanical Energy ◽  
Molecular Gas ◽  
Ionized Gas ◽  
Star Forming ◽  
Stellar Feedback ◽  
Dominant Component ◽  
The Galaxy ◽  
Field Lines

ABSTRACT Stellar feedback plays a significant role in modulating star formation, redistributing metals, and shaping the baryonic and dark structure of galaxies – however, the efficiency of its energy deposition to the interstellar medium is challenging to constrain observationally. Here we leverage HST and ALMA imaging of a molecular gas and dust shell ($M_{\mathrm{ H}_2} \sim 2\times 10^{5}\, {\rm M}_{\odot }$) in an outflow from the nuclear star-forming ring of the galaxy NGC 3351, to serve as a boundary condition for a dynamical and energetic analysis of the outflowing ionized gas seen in our MUSE TIMER survey. We use starburst99 models and prescriptions for feedback from simulations to demonstrate that the observed star formation energetics can reproduce the ionized and molecular gas dynamics – provided a dominant component of the momentum injection comes from direct photon pressure from young stars, on top of supernovae, photoionization heating, and stellar winds. The mechanical energy budget from these sources is comparable to low luminosity active galactic neuclei, suggesting that stellar feedback can be a relevant driver of bulk gas motions in galaxy centres – although here ≲10−3 of the ionized gas mass is escaping the galaxy. We test several scenarios for the survival/formation of the cold gas in the outflow, including in situ condensation and cooling. Interestingly, the geometry of the molecular gas shell, observed magnetic field strengths and emission line diagnostics are consistent with a scenario where magnetic field lines aided survival of the dusty ISM as it was initially launched (with mass-loading factor ≲1) from the ring by stellar feedback. This system’s unique feedback-driven morphology can hopefully serve as a useful litmus test for feedback prescriptions in magnetohydrodynamical galaxy simulations.

scholarly journals X-ray and Ion Emission Sources in High-current Discharge Plasma

2015 ◽  
Vol 71 ◽  
pp. 146-149 ◽  
Author(s):  
A.V. Balovnev ◽  
E.D. Vovchenko ◽  
I.G. Grigoryeva ◽  
E.I. Dodulad ◽  
A.S. Savelov ◽  
...  
Keyword(s):  
Discharge Plasma ◽  
Emission Sources ◽  
High Current ◽  
Current Discharge ◽  
X Ray ◽  
High Current Discharge ◽  
Ion Emission

Comments on the reconnexion rate of magnetic fields

1973 ◽  
Vol 9 (1) ◽  
pp. 49-63 ◽  
Author(s):  
E. N. Parker
Keyword(s):  
Velocity Field ◽  
Magnetic Fields ◽  
Turbulent Flows ◽  
Similarity Solutions ◽  
Neutral Point ◽  
Solar Photosphere ◽  
Complete Field ◽  
Fluid Equations ◽  
The Galaxy

The reconnexion rate of magnetic fields is crucial in understanding the fields found in turbulent flows in the solar photosphere and in the galaxy, and in flare phenomena. This paper examines the behaviour of magnetic fields in the neighbourhood of an X-type neutral point. The treatment is kinematical, specifying the velocity field v and constructing solutions to the hydromagnetic equation for B. The calculations demonstrate that the reconnexion rate is controlled by the diffusion in the near neighbourhood of the neutral point, and is not arbitrarily large, as has been suggested by similarity solutions of the complete field and fluid equations for vanishing diffusion

scholarly journals Magnetic Fields and Ionized Gas in the Inner Galaxy: An Outer Scale for Turbulence and the Possible Role of HiiRegions

2004 ◽  
Vol 609 (2) ◽  
pp. 776-784 ◽  
Author(s):  
M. Haverkorn ◽  
B. M. Gaensler ◽  
N. M. McClure‐Griffiths ◽  
John M. Dickey ◽  
A. J. Green
Keyword(s):  
Magnetic Fields ◽  
Outer Scale ◽  
Ionized Gas

scholarly journals LINER-like emission in red galaxies: evolutionary phase or recurring phenomenon?

2007 ◽  
Vol 3 (S245) ◽  
pp. 181-184
Author(s):  
Genevieve J. Graves
Keyword(s):  
Stellar Population ◽  
Velocity Dispersion ◽  
Large Fraction ◽  
Optical Emission ◽  
Ionized Gas ◽  
Satellite Galaxy ◽  
The Galaxy ◽  
Evolutionary Phase ◽  
Interstellar Material ◽  
Red Galaxies

AbstractWe present recent results showing that a large fraction of red sequence galaxies contain ionized gas with LINER-like optical emission line ratios. This emission is more frequently found in galaxies with lower central velocity dispersion (σ) and these galaxies typically have younger mean ages than galaxies at the same σ which do not host emission. We suggest that the presence of LINER-like emission may be determined by the quantity of interstellar material in these galaxies and may be associated with the recent accretion of a gas-rich satellite galaxy or alternatively with stellar mass loss that declines as the galaxy stellar population ages.

Stellar and Ionized Gas Kinematics in the Circumnuclear Region of the Galaxy NGC 7331

1997 ◽  
Vol 488 (2) ◽  
pp. 682-693 ◽  
Author(s):  
E. Mediavilla ◽  
S. Arribas ◽  
B. Garcia‐Lorenzo ◽  
C. del Burgo
Keyword(s):  
Ionized Gas ◽  
Gas Kinematics ◽  
The Galaxy
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