Direct-current-like phase space manipulation using chirped alternating current fields

Abstract

Waves in plasmas can accelerate particles that are resonant with the wave. A dc electric field also accelerates particles, but without a resonance discrimination, which makes the acceleration mechanism profoundly different. Whereas wave-particle acceleration mechanisms have been widely discussed in the literature, this work discusses the direct analogy between wave acceleration and dc field acceleration in a particular parameter regime explored in previous works. Apart from the academic interest of this correspondence, there may be practical advantages in using waves to mimic dc electric fields, for example, in driving plasma current with high efficiency.

Averaged variational principle for autoresonant Bernstein–Greene–Kruskal modes

“…This asymmetry in the distribution yields a dc current in the plasma, 15 which was analyzed recently in more detail in Ref. 21, as a possible new current drive mechanism. The evolution of the amplitude a 1 of the first spatial harmonic of the self-field and the phase mismatch ⌽ between the first harmonic and the driving wave in our example from Vlasov-Poisson are shown in Fig.…”

Adiabatic nonlinear waves with trapped particles. II. Wave dispersion

“…For example, consider a driven nonlinear mode with adiabatic chirp imposed [10,[43][44][45]. Due to the chirp, the wave phase velocity changes, carrying trapped particles along because of the autoresonance; then F (J < J * ) remains intact.…”