scholarly journals 8. Ionized gas in a magnetic field

1958 ◽  
Vol 6 ◽  
pp. 71-80 ◽  
Author(s):  
A. Schlüter
Keyword(s):  
Magnetic Field ◽  
Conservation Laws ◽  
Hydrodynamic Equation ◽  
Practical Importance ◽  
Equation Of Motion ◽  
Negligible Effect ◽  
Fluid Models ◽  
Mechanical Interaction ◽  
Ionized Gas ◽  
Pressure Diffusion

The ionized gas is described as a mixture of several fluids; each obeying a quasi-hydrodynamic equation of motion with additional terms describing the mechanical interaction. Particularly, two- and three-fluid models are considered. The nature of the approximations (‘quasi-neutrality’, ‘creeping diffusion’) is discussed. Conservation-laws are formulated for the case of negligible effect of mutual encounters and of pressure diffusion. These models lead to a generalization of Ohm's law; it is shown that the additional terms are of practical importance if one has three components, of which one may be neutral.

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.

Exploring the nonextensive thermodynamics of partially ionized gas in magnetic field

2021 ◽  
Vol 104 (4) ◽  
Author(s):  
June Young Kim ◽  
Hyo-Chang Lee ◽  
Geunwoo Go ◽  
Yeong Hwan Choi ◽  
Y. S. Hwang ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Ionized Gas ◽  
Nonextensive Thermodynamics ◽  
Partially Ionized

scholarly journals A qualitative study of a nanotube model using an iterative Taylor method

2017 ◽  
Vol 28 (03) ◽  
pp. 1750036 ◽  
Author(s):  
M. Gadella ◽  
L. P. Lara ◽  
J. Negro
Keyword(s):  
Magnetic Field ◽  
Energy Eigenvalue ◽  
Equation Of Motion ◽  
Minimal Energy ◽  
Approximate Methods ◽  
Symmetry Properties ◽  
Exactly Solvable ◽  
Taylor Method ◽  
Physical Reasons ◽  
Weyl Equation

Physical properties of graphene nanotubes may strongly depend on external fields. In a recent paper V. Jakubský, S. Kuru, J. Negro, J. Phys. A: Math. Theor. 47, 115307 (2014), the authors have studied a model of carbon nanotubes under the presence of an external magnetic field, chosen for some symmetry properties. The model admits an exact solution, provided that the value of a parameter, here denoted as [Formula: see text], be equal to zero. This parameter is the eigenvalue of the component of the momentum in the direction of the nanotube axis. However, it seems that this parameter cannot be discarded for physical reasons. The choice of nontrivial values for this parameter produces an equation of motion for electrons in the nanotube (a Dirac–Weyl equation), which cannot be exactly solvable. Then, we proposed some iterative approximate methods to solve this equation and obtaining its eigenvalues. Some tests have shown that an iterative Taylor method is more efficient than some others we have used. For [Formula: see text], we have found that, excluding the minimal energy eigenvalue, the lowest energy values obtained for [Formula: see text] split into two different ones and, therefore, producing gaps in the energy spectrum.

Motion of a charged particle in superposed Heliotron and biconical cusp fields

1969 ◽  
Vol 3 (2) ◽  
pp. 255-267 ◽  
Author(s):  
M. P. Srivastava ◽  
P. K. Bhat
Keyword(s):  
Magnetic Field ◽  
Charged Particle ◽  
Magnetic Moment ◽  
Particle Trajectory ◽  
Three Dimensional ◽  
Equation Of Motion ◽  
Neutral Point ◽  
Two Dimensional ◽  
Axially Symmetric ◽  
Hybrid Type

We have studied the behaviour of a charged particle in an axially symmetric magnetic field having a neutral point, so as to find a possibility of confining a charged particle in a thermonuclear device. In order to study the motion we have reduced a three-dimensional motion to a two-dimensional one by introducing a fictitious potential. Following Schmidt we have classified the motion, as an ‘off-axis motion’ and ‘encircling motion’ depending on the behaviour of this potential. We see that the particle performs a hybrid type of motion in the negative z-axis, i.e. at some instant it is in ‘off-axis motion’ while at another instant it is in ‘encircling motion’. We have also solved the equation of motion numerically and the graphs of the particle trajectory verify our analysis. We find that in most of the cases the particle is contained. The magnetic moment is found to be moderately adiabatic.

scholarly journals Conservation Laws in Physics – Emmy Noether’s Theorem

2014 ◽  
Vol 29 ◽  
pp. 55-61
Author(s):  
Daniela Manolea
Keyword(s):  
Conservation Laws ◽  
Celestial Body ◽  
Practical Importance ◽  
Microscopic Level ◽  
Human Knowledge ◽  
Noether’S Theorem ◽  
Noether's Theorem ◽  
The World ◽  
Physical Laws ◽  
Practical Impact

The study is explanatory-interpretative and argues the practical character of Physics. It starts from premise that formation of a correct conception of the world begins with the understanding of physics. It is one of the earliest chapters of human knowledge, studying the material world from the microscopic level of the particles to the macroscopic level of the celestial body. As an example for the practical importance of applying the laws of physics take the set of physical laws of conservation, in particular, it explains the practical impact of Emmy Noether's Theorem.

Effects of magnetic field on pulse and CW operation of the large bore ionized gas laser

1967 ◽  
Vol 55 (5) ◽  
pp. 691-692 ◽  
Author(s):  
S.A. Ahmed ◽  
T.J. Faith ◽  
G.W. Hoffman
Keyword(s):  
Magnetic Field ◽  
Ionized Gas ◽  
Gas Laser ◽  
Cw Operation
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