Theory of fast electron transport for fast ignition

Abstract

Abstract. Fast Ignition Inertial Confinement Fusion is a variant of inertial fusion in which DT fuel is first compressed to high density and then ignited by a relativistic electron beam generated by a fast (< 20 ps) ultra-intense laser pulse, which is usually brought in to the dense plasma via the inclusion of a re-entrant cone. The transport of this beam from the cone apex into the dense fuel is a critical part of this scheme, as it can strongly influence the overall energetics. Here we review progress in the theory and numerical simulation of fast electron transport in the context of Fast Ignition. Important aspects of the basic plasma physics, descriptions of the numerical methods used, a review of ignition-scale simulations, and a survey of schemes for controlling the propagation of fast electrons are included. Considerable progress has taken place in this area, but the development of a robust, high-gain FI 'point design' is still an ongoing challenge.

Control of an electron beam using strong magnetic field for efficient core heating in fast ignition

“…In the previous review paper [16], the beam guiding by magnetic-pipe was discussed for the ignition-scale electron beam (the beam energy Eb > 100 kJ, the intensity Ib ~ 10 20 -10 21 W/cm 2 , the pulse duration τb~ 20ps). It was reported that in the case of such high energy beams, the direction of longitudinal B-field affects the guiding performance.…”

Effects of filamentation instability on the divergence of relativistic electrons driven by ultraintense laser pulses

“…Ultraintense laser-driven REs have attracted great recent attention 1,2 due to their potential application in the areas of fast ignition laser fusion [3][4][5][6] , ion acceleration by laser-plasma interaction 7,8 , and production of ultrashort bright radiations 9 . It is essential to characterize accurately the RE divergence for these applications.…”

The effect of grading the atomic number at resistive guide element interface on magnetic collimation

“…The mathematical expressions of the collisional operators are obtained from Davies 13 equations (1) and (2). More details about the physics of hybrid code can be found in the study by Robinson et al 8 A 200 Â 100 Â 100 grid was used with a 0.5 lmc e l ls i z e in each direction. The number of macroparticles injected into each of the cells was 126.…”

“…This implies that the product of B / L / needs to be larger than the fast electron momentum to reflect the fast electrons back towards the guide axis. The resistive guide has been suggested for applications such as the Fast Ignition approach to the inertial confinement fusion scheme 6,7 where the energetic fast electrons need to be guided through an overdense stand-off distance of 100 lm or more 8 and deposited into the compressed core of deuterium-tritium (DT) plasma. It has been suggested that a resistive guide element can also be used as a driver in hydrodynamic experiments 4,9 since strong heating occurs where the fast electron beam is collimated.…”