Guiding and collimating the fast electrons by using a low-density-core target with buried high density layers

Abstract

A low-density-core target with buried high density layers is proposed to improve the transport of fast electrons and involved problems are investigated by using two-dimensional particle-in-cell simulations. It is demonstrated that this target can collimate the fast electrons efficiently and lead to a better beam quality. The enhancement is attributed to the weakening of the two stream instability and the better collimation by the self-generated multilayer megagauss magnetic field as well as the baroclinic magnetic field. Comparing this to that without buried high density layers, the energy flux of fast electrons is increased by a factor of about 1.8 and has a narrower transverse distribution in space. Besides, the dependence of the efficiency on the target parameters is examined, and the optimal target parameters are also obtained. Such a target can be useful to many applications, such as fast ignition in inertial fusion.

Photon and positron production by ultrahigh-intensity laser interaction with various plasma foils

“…PIC simulation is an effective tool for studying certain fields in laser-plasma interaction physics, such as in laser-based particle acceleration, high-energy-density physics, fast ignition in inertial confinement fusion, etc. [33][34][35][36][37]. Since the coupling between the QED processes and plasma dynamics is very complicated, numerical simulations have recently been shown to be an effective way to clearly explore such interactions.…”

Fast electrons collimating and focusing by an ultraintense laser interacting with a high density layers

“…In table 1, the flat target with HDL represents the flat structure in the front part instead of cone structure [18], with the rear part of it being the low density core with HDL on either sides with high density cladding structure [18]. Comparing different target structures, it is shown that the conversion efficiency for the double-cone funnel target with HDL is a factor of 2.2 (73.8%) higher than that without HDL, and a factor of even 3.98 higher than that of the flat target with HDL case.…”

“…Detailed physical analysis shows these enhancement are primarily due to the weakening of the two stream-instability (TSI) and the self-generated magnetic fields produced from interface of different materials. As in our previous work [18] in which the optimal parameter of the HDL widths ranged between 0.2 and 0.3 μm, here too we choose 0.25 μm as the width of HDL for illustration.…”