Dense pair plasma generation and its modulation dynamics in counter-propagating laser field

Abstract

With two-dimensional quantum electrodynamics (QED) particle-in-cell simulations, a dense electron-positron ( e − e + ) pair generation from laser-solid interactions is demonstrated. When the interaction of two linearly polarized laser pulses with a thin target enters into the relativistic transparency regime, a stable standing wave (SW) field can be formed by the overlap of the two counter-propagating laser pulses directly. The present study aims to clarify the effects of the SW field on the dynamics of e − e + pair plasmas. Our results indicate that under the combined effect of the SW field and radiation reaction (RR) effect, the created e − e + pairs can be trapped into the electric field nodes when the field strength is strong. The trapping effect contributes to the generation of γ AV ≥ 400 and ultra-dense pair plasmas in the two-side irradiation scheme. Despite different laser intensities, these pair plasmas have a Maxwellian spectral distribution with a peak energy of 150 MeV. Besides, the periodical modulation of the average energy, spatial, phase-space, and angular patterns of the e − e + pair plasmas can be triggered. In the angular patterns, as long as the SW field exists, pair plasmas can be pinched along the laser polarization direction. These results may offer a better understanding of the laser-solid interactions in the experiments when 10-PW laser facilities come into operation in the future.

Numerical simulation on modulational instability of ion-acoustic waves in plasma

“…In the present paper, we attempt to investigate ion acoustic waves obtained though the reductive perturbation method and discuss modulational instability in the plasma using the one-dimensional electrostatic particle-in-cell (PIC) method. [30,31] This method is a common numerical simulation method used to solve certain classes of partial differential equations. At the beginning of the simulation, super-particles (SPs) are uniformly distributed throughout the region of interest,where each SPs is given a weight factor S that specifies the number of real particles represented.…”

High density γ-ray emission and dense positron production via multi-laser driven circular target

“…One way is to enhance the laser intensity by selecting appropriate polarized lasers [22][23][24] or/and focusing and redistributing the lasers' energy [25][26][27][28]. Another way is to change the plasma target configuration, such as one or multiple laser interactions with near-criticaldensity plasma [29][30][31][32][33][34], solid Al target [35][36][37][38][39][40] or gas plasma [41,42]. Positron beams with a small divergence angle [33] and desirable angular momentum [34] can be obtained in these ways.…”