Particle dynamics in a large-amplitude wave packet

Abstract

A new adiabatic theory permits the understanding of one-dimensional dynamics of particles interacting with a large-amplitude wave packet for bounce time short compared with the transit time. This theory differs from previous ones in that the Hamiltonian varies slowly not with the time, but with the coordinate. The resulting adiabatic invariant is not equal, even in lowest order, to the usual action. This theory predicts the basic features of the interaction observed in previous numerical studies.

Ponderomotive ForcesonWaves in Modulated Media

“…It is hence also natural to extrapolate the wave-particle analogy to the Pockels regime (τ 1), where the interaction is nonadiabatic [4,8]. Based on what is known about the particle dynamics in nonadiabatic ponderomotive barriers [4,8,31], one readily anticipates that regions of strong MW can be arranged in this regime to scatter PW rays probabilistically and, when Ω is nonzero, also asymmetrically. This is confirmed in simulations already for simple MW envelopes (Fig.…”

“…The electric field envelope E is given in units of its maximum amplitude;Ñ is given in units κ The pulse hits the GVR at about k0x ≃ −100; then it is partially transmitted and partially reflected, much like it is described for particles in Ref. [31]. (c) |E(t, x)| for k0 < 0.…”

Generation of ultrafast electrons by simultaneous stimulated Raman backward and forward scattering

“…A simple model [4] [6,7]. The behavior of the electrons can also be bistable: they either get a large velocity increment &om the wave or no velocity increment at all.…”

DC-like Phase Space Manipulation and Particle Acceleration Using Chirped AC Fields

“…There are of course many specific wave mechanisms that have been advanced, such as recently: ponderomotive accelerations where particles exit a ponderomotive potential in an appropriate way [11][12][13][14][15][16][17][18][19][20][21][22][23]; ratchet effects using a cyclotron resonance [24][25][26]; and wakefield acceleration effects [27] including acceleration in plasma channels [28].…”