Synchrotron Radiation Spectra

1972 ◽  
Vol 2 (3) ◽  
pp. 142-144 ◽  
Author(s):  
L. J. Gleeson ◽  
K. C. Westfold
Keyword(s):  
Magnetic Field ◽  
Synchrotron Radiation ◽  
Energy Distribution ◽  
Power Law ◽  
Uniform Magnetic Field ◽  
Charged Particles ◽  
Radiation Spectra ◽  
Field Lines

In this paper we give an account of the corrections that must be made to the formula for the emissivity ηf due to a power-law energy distribution of ultrarelativistic charged particles in a uniform magnetic field B0 in directions well away from the field lines when the effects of upper and lower cut-off values E2 and E1 in the energy distribution are not negligible.

Exact nonlinear wave solutions of the incompressible magnetohydrodynamic equations in a sheared magnetic field

1990 ◽  
Vol 44 (1) ◽  
pp. 25-32 ◽  
Author(s):  
Hiromitsu Hamabata
Keyword(s):  
Magnetic Field ◽  
Incompressible Fluid ◽  
Large Amplitude ◽  
Uniform Magnetic Field ◽  
Magnetohydrodynamic Equations ◽  
Wave Solutions ◽  
Field Lines ◽  
Incompressible Magnetohydrodynamic Equations ◽  
Physical Quantities ◽  
Nonlinear Wave Solutions

Exact wave solutions of the nonlinear jnagnetohydrodynamic equations for a highly conducting incompressible fluid are obtained for the cases where the physical quantities are independent of one Cartesian co-ordina.te and for where they vary three-dimensionally but both the streamlines and magnetic field lines lie in parallel planes. It is shown that there is a class of exact wave solutions with large amplitude propagating in a straight but non-uniform magnetic field with constant or non-uniform velocity.

Magnetic Field Aligned Potentials as an Acceleration Mechanism at Jupiter

2021 ◽  
Author(s):  
Dave Constable ◽  
Licia Ray ◽  
Sarah Badman ◽  
Chris Arridge ◽  
Chris Lorch ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Temporal Evolution ◽  
Charged Particles ◽  
Uniform Mesh ◽  
Time Varying ◽  
Potential Structure ◽  
Field Aligned Current ◽  
Field Lines ◽  
The Magnetic Field ◽  
Insight Into

<p>Since arriving at Jupiter, Juno has observed instances of field-aligned proton and electron beams, in both the upward and downward current regions. These field-aligned beams are identified by inverted-V structures in plasma data, which indicate the presence of potential structures aligned with the magnetic field. The direction, magnitude and location of these potential structures is important, as it affects the characteristics of any resultant field-aligned current. At high latitudes, Juno has observed potentials of 100’s of kV occurring in both directions. Charged particles that are accelerated into Jupiter’s atmosphere and precipitate can excite aurora; likewise, particles accelerated away from the planet can contribute to the population of the magnetosphere.</p> <p>Using a time-varying 1-D spatial, 2-D velocity space Vlasov code, we examine magnetic field lines which extend from Jupiter into the middle magnetosphere. By applying and varying a potential difference at the ionosphere, we can gain insight into the effect these have on the plasma population, the potential structure, and plasma densities along the field line. Utilising a non-uniform mesh, additional resolution is applied in regions where particle acceleration occurs, allowing the spatial and temporal evolution of the plasma to be examined. Here, we present new results from our model, constrained, and compared with recent Juno observations, and examining both the upward and downward current regions.</p>

scholarly journals Particle Acceleration and Radiation in Magnetospheres of Collapsing Stars

2000 ◽  
Vol 195 ◽  
pp. 403-406
Author(s):  
V. Kryvdyk
Keyword(s):  
Magnetic Fields ◽  
Energy Distribution ◽  
Power Law ◽  
Charged Particles ◽  
Particle Dynamics ◽  
Initial Energy ◽  
Particle Energy ◽  
Radiation Fluxes ◽  
Nonthermal Emission ◽  
Initial Power

Particle dynamics and nonthermal emission therefrom in the magnetospheres of collapsing stars with initial dipole magnetic fields and a certain initial energy distribution of charged particles (power-law, relativistic Maxwell, and Boltzmann distributions) are considered. The radiation fluxes are calculated for various collapsing stars with initial dipole magnetic fields and an initial power-law particle energy distribution in the magnetosphere. The effects can be observed by means of modern instruments.

Threshold speed for two-dimensional confinement of charged particles in certain axisymmetric magnetic fields

2018 ◽  
Vol 96 (5) ◽  
pp. 519-523 ◽  
Author(s):  
K. Kabin ◽  
G. Kalugin ◽  
E. Spanswick ◽  
E. Donovan
Keyword(s):  
Magnetic Field ◽  
Power Law ◽  
Critical Speed ◽  
Longitudinal Magnetic Field ◽  
Strong Dependence ◽  
Charged Particles ◽  
Transcendental Equation ◽  
Power Exponent ◽  
Magnetic Field Magnitude ◽  
The Magnetic Field

In this paper we discuss conditions under which charged particles are confined by an axisymmetric longitudinal magnetic field with power law dependence on the radius. We derive a transcendental equation for the critical speed corresponding to the threshold between bounded and unbounded trajectories of the particles. This threshold speed shows strong dependence on the direction, and this dependence becomes more prominent as the exponent of the power law increases. The equation for threshold speed can be solved exactly for several specific values of the power exponent, but in general it requires a numerical treatment. Remarkably, if the magnetic field magnitude decreases more slowly than the inverse of the radius, charged particles remain confined no matter how large their energies may be.

scholarly journals Guiding-centre transformation of the radiation–reaction force in a non-uniform magnetic field

2015 ◽  
Vol 81 (5) ◽  
Author(s):  
E. Hirvijoki ◽  
J. Decker ◽  
A. J. Brizard ◽  
O. Embréus
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Uniform Magnetic Field ◽  
Reaction Force ◽  
Charged Particles ◽  
Collision Operator ◽  
Radiation Reaction ◽  
Transform Method ◽  
Lie Transform ◽  
Radiation Reaction Force

In this paper, we present the guiding-centre transformation of the radiation–reaction force of a classical point charge travelling in a non-uniform magnetic field. The transformation is valid as long as the gyroradius of the charged particles is much smaller than the magnetic field non-uniformity length scale, so that the guiding-centre Lie-transform method is applicable. Elimination of the gyromotion time scale from the radiation–reaction force is obtained with the Poisson-bracket formalism originally introduced by Brizard (Phys. Plasmas, vol. 11, 2004, 4429–4438), where it was used to eliminate the fast gyromotion from the Fokker–Planck collision operator. The formalism presented here is applicable to the motion of charged particles in planetary magnetic fields as well as in magnetic confinement fusion plasmas, where the corresponding so-called synchrotron radiation can be detected. Applications of the guiding-centre radiation–reaction force include tracing of charged particle orbits in complex magnetic fields as well as the kinetic description of plasma when the loss of energy and momentum due to radiation plays an important role, e.g. for runaway-electron dynamics in tokamaks.

Diffusion eines Plasmas in Abhängigkeit von Magnetfeld und Drude und von der Längs-Ausdehnung in Magnetfeldrichtung

1963 ◽  
Vol 18 (8-9) ◽  
pp. 889-895
Author(s):  
F. Schwirzke
Keyword(s):  
Magnetic Field ◽  
Density Profile ◽  
Plasma Column ◽  
Uniform Magnetic Field ◽  
Radial Density ◽  
Radial Density Profile ◽  
Radial Density Distribution ◽  
Field Lines ◽  
Different Gases ◽  
The Magnetic Field

The radial density distribution for a plasma in a uniform magnetic field was studied in dependence of pressure and distance of the conducting end plates. It was possible to confirm experimentally the dependence of the radial distribution of the finite length in direction of the field lines. The influence of the magnetic field, of the pressure, and of the length of the plasma column on the radial density profile is, in different gases, qualitatively in accordance with the “short-circuiting” theory of A. SIMON.

The distortion of a magnetic field by the flow of a conducting fluid past a circular cylinder

1965 ◽  
Vol 22 (3) ◽  
pp. 561-578 ◽  
Author(s):  
R. Seebass ◽  
K. Tamada
Keyword(s):  
Magnetic Field ◽  
Integral Equation ◽  
Circular Cylinder ◽  
Potential Flow ◽  
Uniform Magnetic Field ◽  
The Body ◽  
Flow Potential ◽  
Field Lines ◽  
The Magnetic Field ◽  
Rear Stagnation Point

The distortion of a uniform magnetic field, aligned with the flow at infinity, by the potential flow of an inviscid conductor about a circular cylinder is determined. Potential flow of the fluid occurs when the interaction parameter is small; this is the case studied here. In the flow-potential and stream-function plane the problem may be formulated as a singular integral equation. Solutions of this equation show that for small fluid conductivities the magnetic field lines are distorted in the sense of being dragged along by the motion of the fluid. This process continues as the conductivity increases, with fewer and fewer of the magnetic field lines entering the body. For large conductivity this reduced flux of field lines enters over most of the body surface and exits in the neighbourhood of the rear stagnation point; behind the body there is a jet-like structure of magnetic field lines.

The nonlinear breakup of a magnetic layer: instability to interchange modes

1988 ◽  
Vol 196 ◽  
pp. 323-344 ◽  
Author(s):  
F. Cattaneo ◽  
D. W. Hughes
Keyword(s):  
Magnetic Field ◽  
Uniform Magnetic Field ◽  
Magnetic Layer ◽  
Mhd Equations ◽  
Strong Interactions ◽  
Compressible Mhd Equations ◽  
Rayleigh Taylor Instability ◽  
Basic States ◽  
Field Lines ◽  
The Magnetic Field

Motivated by considerations of the solar toroidal magnetic field we have studied the behaviour of a layer of uniform magnetic field embedded in a convectively stable atmosphere. Since the field can support extra mass, such a configuration is top-heavy and thus instabilities of the Rayleigh-Taylor type can occur. For both static and rotating basic states we have followed the evolution of the interchange modes (no bending of the field lines) by integrating numerically the nonlinear compressible MHD equations. The initial Rayleigh-Taylor instability of the magnetic field gives instabilities to strong shearing motions, thereby exciting secondary Kelvin-Helmholtz instabilities which wrap the gas into regions of intense vorticity. The subsequent motions are determined primarily by the strong interactions between vortices which are responsible for the rapid disruption of the magnetic layer.

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