Physics of laser plasma interaction and particle transport in the context of inertial confinement fusion

V.T Tikhonchuk

doi:10.1088/1741-4326/aab21a

Abstract

Lasers are unique tools for transporting extremely high powers over large distances, but transfer of such a power from photons to matter in small volumes is a very complicated problem. First of all, the interaction proceeds very far from equilibrium, as with photons having energy of a few electron-volts one would like to heat plasma to temperatures thousand times higher. Second, these processes are strongly nonlinear, as they correspond to transfer energies of a large number of photons to a much smaller number of charged particles in extremely small volumes and in very short time scales. Research in inertial confinement fusion (ICF) gave a strong push for studying all these processes in detail, and now, although many issues remain to be resolved, we have quite a good understanding of how they operate in ICF conditions and what limitations and advantages they offer.In this short review, I share my personal recollections of almost 50 years history of the physics of laser plasma interaction. Understanding of highly nonlinear microscopic processes allowed us to improve the hydrodynamic performance of ICF targets and to foresee future developments. The key point is that multiscale modeling allowed for the retainment of major elements of microscopic physics in macroscopic hydrodynamic codes and make them more accurate and predictive.

Highlights

I share my personal recollections of almost 50 years history of the physics of laser plasma interaction
Understanding of highly nonlinear microscopic processes allowed us to improve the hydrodynamic performance of inertial confinement fusion (ICF) targets and to foresee future developments
We have developed one of the first non-paraxial electromagnetic codes, which gave us access to a number of interesting effects related to competition of the beam self-focusing, cross beam energy transfer (CBET) and SBS in two- and three-dimensional geometry

Summary

Introduction: historical outlook

The processes of laser plasma interaction and particle transport operate on the micrometric and picosecond time scales, which are two-three orders of magnitude smaller than the scales of inertial confinement fusion (ICF) targets. In the beginning of the 1970s, the parametric instabilities in a homogeneous plasma were already known and the theory has been partially compared with experiments There was another important point—accounting for the plasma spatial inhomogeneity. The theory of parametric instabilities in an inhomogeneous plasma with application to laser plasma interactions has been developed in the joint Russian-French-US publication [22] followed by a mode detailed analysis [23]. With these seminal papers the general background of the theory of parametric instabilities has been laid. A lot more work was needed to bring it to realistic laser plasma interaction conditions

Parametric instabilities in laser produced plasmas

Findings

Nonlocal electron transport