Multidimensional electron beamplasma instabilities in the relativistic regime
Abstract
The interest in relativistic beamplasma instabilities has been greatly rejuvenated over the past two decades by novel concepts in laboratory and space plasmas. Recent advances in this longstanding field are here reviewed from both theoretical and numerical points of view. The primary focus is on the twodimensional spectrum of unstable electromagnetic waves growing within relativistic, unmagnetized, and uniform electron beamplasma systems. Although the goal is to provide a unified picture of all instability classes at play, emphasis is put on the potentially dominant waves propagating obliquely to the beam direction, which have received little attention over the years. First, the basic derivation of the general dielectric function of a kinetic relativistic plasma is recalled. Next, an overview of twodimensional unstable spectra associated with various beamplasma distribution functions is given. Both coldfluid and kinetic linear theory results are reported, the latter being based on waterbag and MaxwellJüttner model distributions. The main properties of the competing modes (developing parallel, transverse, and oblique to the beam) are given, and their respective region of dominance in the system parameter space is explained. Later sections address particleincell numerical simulations and the nonlinear evolution of multidimensional beamplasma systems. The elementary structures generated by the various instability classes are first discussed in the case of reducedgeometry systems. Validation of linear theory is then illustrated in detail for largescale systems, as is the multistaged character of the nonlinear phase. Finally, a collection of closely related beamplasma problems involving additional physical effects is presented, and worthwhile directions of future research are outlined.
 Publication:

Physics of Plasmas
 Pub Date:
 December 2010
 DOI:
 10.1063/1.3514586
 Bibcode:
 2010PhPl...17l0501B
 Keywords:

 filamentation instability;
 plasma dielectric properties;
 plasma electromagnetic wave propagation;
 plasma kinetic theory;
 plasma nonlinear processes;
 plasma simulation;
 relativistic plasmas;
 52.35.Py;
 52.27.Ny;
 52.25.Mq;
 52.25.Dg;
 52.35.Mw;
 52.65.Rr;
 Macroinstabilities;
 Relativistic plasmas;
 Dielectric properties;
 Plasma kinetic equations;
 Nonlinear phenomena: waves wave propagation and other interactions;
 Particleincell method