14 research outputs found
Scattering and Transformation of Waves on Heavy Particles in Magnetized Plasma
The scattering and transformation of the waves propagating in magnetized
plasma on a heavy stationary charged particle located at a plane plasma-vacuum
boundary is considered. The scattering (transformation) occurs due to the
nonlinear coupling of the incident wave with the polarization (shielding) cloud
surrounding the particle. It is shown that the problem is reduced to the
determination of the nonlinear (three index) dielectric tensor of magnetized
plasma. The angular distribution and the cross section for scattering
(transformation) of high-frequency ordinary and extraordinary waves and
low-frequency upper-hybrid, low-hybrid, and magnetosonic waves are investigated
within a cold plasma (hydrodynamic) model.Comment: 14 pages, 6 figure
On some generalized stopping power sum rules
The Lindhard-Winther (LW) equipartition sum rule shows that within the linear
response theory, the stopping power of an energetic point-charge projectile in
a degenerate electron gas medium, receives equal contributions from
single-particle and collective excitations in the medium. In this paper we show
that the LW sum rule does not necessarily hold for an extended projectile ion
and for ion-clusters moving in a fully degenerate electron gas. We have derived
a generalized equipartition sum rule and some related sum rules for this type
of projectiles. We also present numerical plots for He ion and He
ion-clusters.Comment: 2 figures, LaTe
An exact solution of the moving boundary problem for the expansion of a plasma cylinder in a magnetic field
An exact analytic solution has been obtained for a uniformly expanding,
neutral, infinitely conducting plasma cylinder in an external uniform and
constant magnetic field. The electrodynamical aspects related to the emission
and transformation of energy have been considered as well. The results obtained
can be used in analysing the recent experimental and simulation data.Comment: 5 pages, 1 figur
Stopping Power of Ions in a Magnetized Plasma: Binary Collision Formulatio
In this chapter, we investigate the stopping power of an ion in a magnetized electron plasma in a model of binary collisions (BCs) between ions and magnetized electrons, in which the two-body interaction is treated up to the second order as a perturbation to the helical motion of the electrons. This improved BC theory is uniformly valid for any strength of the magnetic field and is derived for two-body forces which are treated in Fourier space without specifying the interaction potential. The stopping power is explicitly calculated for a regularized and screened potential which is both of finite range and less singular than the Coulomb interaction at the origin. Closed expressions for the stopping power are derived for monoenergetic electrons, which are then folded with an isotropic Maxwell velocity distribution of the electrons. The accuracy and validity of the present model have been studied by comparisons with the classical trajectory Monte Carlo numerical simulations
A number-conserving linear response study of low-velocity ion stopping in a collisional magnetized classical plasma
The results of a theoretical investigation on the low-velocity stopping power
of the ions moving in a magnetized collisional plasma are presented. The
stopping power for an ion is calculated employing linear response theory using
the dielectric function approach. The collisions, which leads to a damping of
the excitations in the plasma, is taken into account through a
number-conserving relaxation time approximation in the linear response
function. In order to highlight the effects of collisions and magnetic field we
present a comparison of our analytical and numerical results obtained for a
nonzero damping or magnetic field with those for a vanishing damping or
magnetic field. It is shown that the collisions remove the anomalous friction
obtained previously [Nersisyan et al., Phys. Rev. E 61, 7022 (2000)] for the
collisionless magnetized plasmas at low ion velocities. One of major objectives
of this study is to compare and contrast our theoretical results with those
obtained through a novel diffusion formulation based on Dufty-Berkovsky
relation evaluated in magnetized one-component plasma models framed on target
ions and electrons.Comment: Submitted to Phys. Rev. E, 17 pages, 4 figure
Instabilities for a relativistic electron beam interacting with a laser irradiated plasma
The effects of a radiation field (RF) on the unstable modes developed in
relativistic electron beam--plasma interaction are investigated assuming that
, where is the frequency of the RF and
is the plasma frequency. These unstable modes are parametrically
coupled to each other due to the RF and are a mix between two--stream and
parametric instabilities. The dispersion equations are derived by the
linearization of the kinetic equations for a beam--plasma system as well as the
Maxwell equations. In order to highlight the effect of the radiation field we
present a comparison of our analytical and numerical results obtained for
nonzero RF with those for vanishing RF. Assuming that the drift velocity
of the beam is parallel to the wave vector of the
excitations two particular transversal and parallel configurations of the
polarization vector of the RF with respect to are
considered in detail. It is shown that in both geometries resonant and
nonresonant couplings between different modes are possible. The largest growth
rates are expected at the transversal configuration when is
perpendicular to . In this case it is demonstrated that in general
the spectrum of the unstable modes in -- plane is split into two
distinct domains with long and short wavelengths, where the unstable modes are
mainly sensitive to the beam or the RF parameters, respectively. In parallel
configuration, , and at short wavelengths
the growth rates of the unstable modes are sensitive to both beam and RF
parameters remaining insensitive to the RF at long wavelengths.Comment: 23 pages, 5 figure
Dicluster Stopping in a Degenerate Electron Gas
In this paper we report on our theoretical studies of various aspects of the
correlated stopping power of two point-like ions (a dicluster) moving in close
but variable vicinity of each other in some metallic target materials the
latter being modelled by a degenerate electron gas with appropriate densities.
Within the linear response theory we have made a comprehensive investigation of
correlated stopping power, vicinage function and related quantities for a
diproton cluster in two metallic targets, aluminum and copper, and present
detailed and comparative results for three approximations to the electron gas
dielectric function, namely the plasmon-pole approximation without and with
dispersion as well as with the random phase approximation. The results are also
compared, wherever applicable, with those for an individual projectile.Comment: 29 figures, LaTe