Towards bright gamma-ray flash generation from tailored target irradiated by multi-petawatt laser

Abstract

One of the remarkable phenomena in the laser-matter interaction is the extremely efficient energy transfer to $$\gamma $$ γ -photons, that appears as a collimated $$\gamma $$ γ -ray beam. For interactions of realistic laser pulses with matter, existence of an amplified spontaneous emission pedestal plays a crucial role, since it hits the target prior to the main pulse arrival, leading to a cloud of preplasma and drilling a narrow channel inside the target. These effects significantly alter the process of $$\gamma $$ γ -photon generation. Here, we study this process by importing the outcome of magnetohydrodynamic simulations of the pedestal-target interaction into particle-in-cell simulations for describing the $$\gamma $$ γ -photon generation. It is seen that target tailoring prior the laser-target interaction plays an important positive role, enhancing the efficiency of laser pulse coupling with the target, and generating high energy electron-positron pairs. It is expected that such a $$\gamma $$ γ -photon source will be actively used in various applications in nuclear photonics, material science and astrophysical processes modelling.

Optimization and control of synchrotron emission in ultraintense laser–solid interactions using machine learning

“…For normal incidence in figure 8(d), every half laser cycle the electric field pulls electrons from the edges towards the centre, with the electrons periodically coming from different sides of the focal spot due to the oscillating direction of the laser electric field. This results in periodic synchrotron radiation at the laser frequency with the lobes separated by half a laser cycle, as observed in reference [28] . The shallow depth of the front surface plasma cavity means that only electrons propagating at a steep angle with the incoming laser pulse move into and experience the highest fields.…”

“…This results in periodic synchrotron radiation at the laser frequency with the lobes separated by half a laser cycle, as observed in Ref. [28]. The shallow depth of the front surface plasma cavity means that only electrons propagating at a steep angle with the incoming laser pulse move into and experience the highest fields.…”

“…Optimization of total synchrotron emission with produces a peak in the angle-resolved synchrotron emission of similar magnitude to the optimum for in Figure 7(c), inadvertently maximizing both objectives. This optimum exhibits a pronounced double-peaked structure in the angular emission characteristic of synchrotron radiation from solid targets [ 26 – 28 , 32 , 57 , 62 ] . However, the 38° angle-of-incidence has resulted in the suppression of the lobe in the direction closer to the perpendicular of the rotated target surface and the enhancement of the lobe closer to the parallel.…”

“…All-optical demonstrations of radiation reaction with much lower laser intensities have been performed [22,23] in which a laser wakefield accelerated electron beam was collided with a laser pulse. Although higher laser intensities are required for the synchrotron radiation to become measurable in laser-solid interactions, theoretical and numerical studies indicate the generation of a high-power gamma ray flash with of the order of 10% conversion efficiency from the laser energy possible [24][25][26][27][28][29] . A large number of different interaction geometries and schemes have been proposed to enhance the gamma ray generation and associated pair production .…”

Instruments for best target position determination in the high-intensity laser-solid interaction experiment

“…High-intensity laser-solid interaction 1 is an important way of generating high harmonics 2,3,4 in the extreme ultraviolet and soft X-ray spectral ranges, as well as to accelerate electrons 5 and ions 6,7,8 and produce gamma rays 9,10 . In experiments with tight focusing 11 of multi-joule femtosecond laser pulses into a ~1-µm focal spot with an ultrarelativistic intensity of ~10 22 W/cm 2 , one of the most critical issues is the precise positioning of the target within the super-short Rayleigh length which is of the order of ~10 µm.…”