Kinetic phenomena of helical plasma waves with orbital angular momentum

Abstract

An accurate description of plasma waves is fundamental for the understanding of many plasma phenomena. It is possible to twist plasma waves such that, in addition to having longitudinal motion, they can possess a quantized orbital angular momentum. One such type of plasma wave is the Laguerre–Gaussian mode. Three-dimensional numerical particle-in-cell simulations demonstrate the existence of stable long-lived plasma waves with orbital angular momentum. These waves can be shown to create large amplitude static magnetic fields with unique twisted longitudinal structures. In this paper, we review the recent progress in studies of helical plasma waves and present a new analytical description of a standing Laguerre–Gaussian plasma wave mode along with 3D particle-in-cell simulation results. The Landau damping of twisted plasma waves shows important differences compared to standard longitudinal plasma wave Landau damping. These effects include an increased damping rate, which is affected by both the focal width and the orbital number of the plasma wave. This increase in the damping rate is of the same order as the thermal correction. Moreover, the direction of momentum picked up by resonant particles from the twisted plasma wave can be significantly altered. By contrast, the radial electric field has a subtle effect on the trajectories of resonant electrons.

Direct spatiotemporal manipulation mechanism to generate spatiotemporally coupled ultrafast light fields

“…To verify the proposed mechanism, an exemplary experiment to generate a single-coil LS is designed and performed. Measurements show that the singlecoil LS generated has tunable and broadband spectral topological charge (TC), which has great potential applications in laser-plasma dynamics [35][36][37] and laser-driven electron acceleration applications [38,39]. To the best of our knowledge, a single-coil LS with a wide TC bandwidth has not previously been realized experimentally since it was initially proposed in 2015.…”

Direct space–time manipulation mechanism for spatio-temporal coupling of ultrafast light field

“…To validate the proposed mechanism, an exemplary experiment to generate a single-coil LS is designed and conducted. Measurements show that the single-coil LS possesses a tunable topological charge (TC) with a broad TC bandwidth, leveraging great potential applications in laserplasma dynamics [30][31][32] , information encoding 33 and laser-driven electron acceleration applications 34,35 . Notably, the unique angular delay of the single-coil LS can serve as the light source for annular on-chip dielectric laser-based accelerators.…”

Generating axial magnetic fields via two plasmon decay driven by a twisted laser

“…When getting absorbed and decaying into a pair of daughter waves, an OAM laser is expected to transport OAM to its daughter waves via three-wave coupling due to the angular momentum conservation. Although both an electron plasma wave (EPW) [11][12][13][14] and an ion-acoustic wave (IAW) [15] can appear as a Laguerre-Gauss (LG) mode that carries OAM in a plasma, the OAM absorption from a laser into such a wave through LPI is not that efficient. The OAM transportation in paraxial LPI scenarios for Stimulated Raman/Brillouin Scattering (SRS/SBS), whose two daughter waves include a scattered light (electromagnetic) wave and an EPW/IAW has been analytically modeled and numerically simulated [5][6][7]10].…”