Relativistic Charged Particle Beam Research Articles

Numerical simulation of the dynamics of an intense relativistic beam of charged particles

A method for the numerical simulation of stochastic processes in intense relativistic beams of particles moving in electric and magnetic fields is described. A two-dimensional approximation using “coarse particles” is considered. The action functions are first tabulated with respect to three variables. The method combines high speed and good accuracy. The results of a simulation are presented.

A Two-Dimensional Intense Relativistic Beam Equilibrium

The behavior of an intense relativistic charged particle beam is studied by determining a two-dimensional equilibrium solution of the laminar flow, monoenergetic particle dynamics equations. With these relations formulated in azimuthally symmetric cylindrical coordinates, the free parameter method is used to derive the most general similarity variable nf(r,z) appropriate to the equations and an exact solution is found in terms of this unknown. The solution is interpreted as a force-free converging or diverging particle beam propagating in the z direction within a conical drift chamber.

Low-frequency hydromagnetic kink mode of a relativistic beam

An analysis of the stability of the kink mode of a relativistic charged-particle beam propagating in a toroidally confined plasma is presented. The essential feature is the treatment of the beam as a distinct component of the system having finite velocity and inertia in addition to its current. To simplify the analysis, the plasma background is assumed to be a pressureless, uniform fluid obeying the laws of perfect magnetohydrodynamics while the beam is treated as a cold, rigid body. To simulate toroidal geometry, periodic boundary conditions are imposed in the axial direction of a straight, cylindrical volume. The walls of the cylinder have perfect conductivity. A strong solenoidal field is externally imposed, but the beam is the only source of the poloidal field. It is found that a modification of the stability condition of Kruskal and Shafranov applies; the onset of instability corresponds to the appearance of closed particle orbits rather than the more severe condition of closed field lines. The maximum rotational transform consistent with stability is ι/ 2π = 1 + (βz γmc2) / (e R 0 Bz).

Beam-plasma interaction as affected by an “axial” inhomogeneity

The effect of axial (with respect to the direction of beam propagation) inhomogeneity on the process of slow surface wave (SW) resonant excitation by a relativistic monoenergetic beam of charged particles is investigated. The allowance for the inhomogeneity is demonstrated to change the natural frequencies of excited SW and thus violate the Cherenkov SW-beam-resonance. A dispersion equation and growth rates of the excited waves are obtained, taking into account the density inhomogeneity.