Coherent relativistic wake wave of a charged object moving steadily in a plasma

Abstract

Nonlinear electron plasma waves driven by a finite-charged particle pulse or rigid object moving at relativistic speeds are investigated. Quasi-stationary smooth and spiky wake waves comoving with the object are found. Localized soliton-like solutions are also shown to exist. Relativistic effects tend to prevent their formation because of the electron mass increase. The application of the very-large-amplitude wake density waves as a source of ultrahigh-energy cosmic-ray events is discussed.

Shielding of moving line charges

“…Physically, this result can be attributed to the fact that when V is sufficiently large, the phase velocity of the excited plasma waves can become so small that the waves become self trapped and cannot propagate away from a finite region near the line charge. It may be of interest to point out that quasistationary plasma wave solitons without external driver have also been reported earlier [14][15][16][17][18]. However, the latter are characterized by density humps (instead of dips like here) with broad bases and narrow peaks, and have been attributed to highly localized balance between the wave dispersion and nonlinearity.…”

Formation of charged-grain clusters

“…The attractive potential, although usually weak, has a power-law dependence on the distance between the grains, and is therefore unshielded and long ranged [4,5,15]. This model is expected to be valid if the grain velocities (and thus the system temperature) are not too large since it does not include wakefield effects of the moving charged particles [23][24][25][26]. It is also consistent with some of the observed properties of highly charged grains [3,5,8,16,[18][19][20].…”

On the formation process of charged clusters

“…The reason is that more quantitative analysis of the simulated results turns out to be difficult since one cannot isolate any cluster, which is an integral part of the self-consistent system of clusters. Aside from being of basic research interest, a better understanding of the clustering process is also useful for the possible control of the final state, which is important for the design and plasma-assisted fabrication of novel functional materials, as well as for interpreting observed phenomena in space and laboratory plasmas [1][2][3][4][5][6][7][8][9][10][11][27][28][29].…”

“…The complex dynamics and interaction of charged grains or objects in plasma have attracted much attention because to a certain degree they resemble that of the microscopic ions, and can play important roles in many astrophysical phenomena [1][2][3][4][5][6][7]. They are also relevant to many practical applications, such as in plasma deposition, etching and sputtering, as well as in manufacturing of integrated circuits in the semiconductor industry [8][9][10][11][12].…”