Effects of radiation reaction in the interaction between cluster media and high intensity lasers in the radiation dominant regime

Abstract

Interaction between media composed of clusters and high intensity lasers in the radiation dominant regime, i.e., intensity of 1022−23 W/cm2, is studied based on the particle-in-cell simulation that includes the radiation reaction. By introducing target materials that have the same total mass but different internal structures, i.e., uniform plasma and cluster media with different cluster radii, we investigate the effect of the internal structure on the interaction dynamics, high energy radiation emission, and its reaction. Intense radiation emission is found in the cluster media where electrons exhibit non-ballistic motions suffering from strong accelerations by both the penetrated laser field and charge separation field of clusters. As a result, the clustered structure increases the energy conversion into high energy radiations significantly at the expense of the conversion into particles, while the total absorption rate into radiation and particles remains unchanged from the absorption rate into particles in the case without radiation reaction. The maximum ion energy achieved in the interaction with cluster media is found to be decreased through the radiation reaction to electrons into the same level with that achieved in the interaction with the uniform plasma. The clustered structure thus enhances high energy radiation emission rather than the ion acceleration in the considered intensity regime.

Plasma density limits for hole boring by intense laser pulses

“…With the development of kiloJoule class high-power lasers, intense pulses of laser light in the relativistic intensity level exceeding 10 18 W μm 2 cm −2 with picosecond (ps) to multi-ps pulse duration are now available at LFEX 1 , NIF-ARC 2 , LMJ-PETAL 3 , and OMEGA-EP 4 . Laser-matter interactions in the relativistic regime have opened up various applications such as relativistic electron beam generation, fast-ion acceleration 5 – 14 , mega-Gauss level magnetic field generation 15 – 17 , intense X-ray 18 , gamma-ray 19 , 20 , positron 21 and neutron 22 generations, and fast-ignition-based laser fusion 23 , 24 . For these applications, energy absorption 25 and momentum transfer from high-intensity lasers to plasma particles are fundamental issues.…”

Electron acceleration in dense plasmas heated by a picosecond relativistic laser

“…For fast ignition-based laser fusion, to know the function shape and the average energy of fast electrons is important in estimating the heating of the core plasma [9,10,28]. The distribution function is also critical to determine the spectrum of x-/gamma-ray radiation from laserheated interactions [6][7][8]. To control the energetic electron generation is a key to create electron-positron pairs through laser-plasma interactions [29][30][31].…”

Laser-driven multi-MeV high-purity proton acceleration via anisotropic ambipolar expansion of micron-scale hydrogen clusters

“…Here, to increase the possibility of high-purity proton acceleration, we employ a different approach using micron-scale hydrogen clusters with a spherical shape 31,32 , which is an alternative to other types of hydrogen targets that allows very efficient coupling with laser pulses compared to planer-shaped targets 33 , thus exhibiting prominent linear and nonlinear dynamics and associated optical properties [34][35][36] even in the radiation-dominant regime 37 . Notably, unlike previous approaches with the nanometer-scale hydrogen clusters [38][39][40][41][42] , this approach uses micron-scale hydrogen clusters, which exhibit a unique laser-cluster interaction.…”