Whistleron gas in magnetized plasmas

Abstract

We have studied the nonlinear dynamics of whistler waves in magnetized plasmas. Since plasmas and beam-plasma systems considered here are assumed to be weakly collisional, the point of reference for the analysis performed in the present paper is the system of hydrodynamic and field equations. We have applied the renormalization group method to obtain dynamical equations for the slowly varying amplitudes of whistler waves. Further, it has been shown that the amplitudes of eigenmodes satisfy an infinite system of coupled nonlinear Schrödinger equations. In this sense, the whistler eigenmodes form a sort of a gas of interacting quasiparticles, while the slowly varying amplitudes can be considered as dynamical variables heralding the relevant information about the system. An important feature of our description is that whistler waves do not perturb the initial uniform density of plasma electrons. The plasma response to the induced whistler waves consists in velocity redistribution which follows exactly the behaviour of the whistlers. In addition, selection rules governing the nonlinear mode coupling have been derived, which represent another interesting peculiarity of our description.

Instability of wave modes in a two-stream free-electron laser with a helical wiggler and an axial magnetic field

“…It has been known for a long time long that the unstable spectrum is not restricted to modes with wave-vector parallel to the flow. 19 A recent review 20 reported the potential dominant unstable waves propagating obliquely to the beam direction without a wiggler field. Therefore, propagation of unstable modes in the oblique direction related to the two-stream instabilities in our configuration might be important in the absence of the wiggler.…”

Relativistic nonlinear whistler waves in cold magnetized plasmas

“…It is however possible to carry out a full reduction, but the resultant amplitude equations comprise an infinite set of coupled nonlinear Schrodinger equations. In this case, one can think of a gas consisting of mutually interacting quasi-particles (whistlerons) 21 .…”

Propagation and Interaction of Electrostatic and Electromagnetic Waves in Two Stream Free Electron Laser in the Presence of Self-Fields

“…Two-stream free electron lasers (TSFEL), FELs in which two beams copropagate with different beam velocities, have been studied during the last few decades [15][16][17][18][19][20][21][22]. Twostream was first proposed by Bekefi and Jacobs for use in FELs [23].…”