Lagrangian-Eulerian Micromotion and Wave Heating in Nonlinear Self-Excited Dust-Acoustic Waves

Abstract

We investigate particle-wave microdynamics in the large amplitude self-excited dust acoustic wave at the discrete level through direct visualization. The wave field induces dust oscillations which in turn sustain wave propagation. In the regular wave with increasing wave amplitude, dust-wave interaction with uncertain temporary crest trapping and dust-dust interaction lead to the transition from cyclic to disordered dust motion associated with the liquid to the gas transition, and anisotropic non-Gaussian heating. In the irregular wave, particle trough-trapping is also observed, and the heating is nearly Gaussian and less anisotropic.

The Structure of Self-Excited Dust-Density Waves Under Microgravity

“…DDWs were studied extensively in the laboratory in dc plasmas [4]- [6] as well as in radio-frequency (RF) discharges [7]. Unfortunately, those measurements are influenced by the gravitational force which introduces an unwanted preferred direction to the system.…”

Plasma physics - A frontier in science of matter

“…b)Coulomb crystal, c) Coulomb liquid, and d) Dust acoustic wave. ( Courtesy of Prof. Lin I ) [79], [36] …”

Volumetric measurements of a spatially growing dust acoustic wave

“…To obtain a measure of the instantaneous properties the wave mode, we use a characteristic feature of the DAW that has been observed in previous measurements; 17,27,32 namely, that bulk motion of the dust grains are correlated with the wave structure that is seen in the dust density perturbations of the wave. In particular, the velocity vectors associated with the particle motion in the wave front point in the direction of wave propagation, while velocity vectors associated with the particle motion on either side of the wave front point in the direction opposite of the wave propagation.…”