Description
Book SynopsisThis textbook provides a comprehensive introduction to the physics of laser-plasma interactions (LPI), based on a graduate course taught by the author. The emphasis is on high-energy-density physics (HEDP) and inertial confinement fusion (ICF), with a comprehensive description of the propagation, absorption, nonlinear effects and parametric instabilities of high energy lasers in plasmas.
The recent demonstration of a burning plasma on the verge of nuclear fusion ignition at the National Ignition Facility in Livermore, California, has marked the beginning of a new era of ICF and fusion research. These new developments make LPI more relevant than ever, and the resulting influx of new scientists necessitates new pedagogical material on the subject. In contrast to the classical textbooks on LPI, this book provides a complete description of all wave-coupling instabilities in unmagnetized plasmas in the kinetic as well as fluid pictures, and includes a comprehensive description of the optical smoothing techniques used on high-power lasers and their impact on laser-plasma instabilities. It summarizes all the key developments from the 1970s to the present day in view of the current state of LPI and ICF research; it provides a derivation of the key LPI metrics and formulas from first principles, and connects the theory to experimental observables.
With exercises and plenty of illustrations, this book is ideal as a textbook for a course on laser-plasma interactions or as a supplementary text for graduate introductory plasma physics course. Students and researchers will also find it to be an invaluable reference and self-study resource.
Table of Contents1.1 Introduction to plasmas (definitions, common plasma parameters)
1.2 Kinetic description of plasmas
1.3 Plasmas as fluids
1.4 Plasma expansion in vacuum
1.5 Collisions in plasmas
1.6 Waves in plasmas
1.6.1 Longitudinal (plasma) waves
1.6.2 Transverse (electromagnetic) waves
1.7 Landau damping in electron or ion plasma waves
1.8 Ion acoustic waves and damping in multi-species plasmas
1.9 Collisional absorption of EMWs and EPWs
2 Single particle dynamics in light waves and plasma waves
2.1 Particle dynamics in a uniform light wave
2.1.1 Non-relativistic quiver motion
2.1.2 Relativistic “figure of eight”
2.2 Particle dynamics in a uniform plasma wave
2.2.1 Non-relativistic wave velocity
2.2.2 Landau damping and wave-particle interaction
2.2.3 Particle approach to wave-breaking
2.2.4 Relativistic wave velocities and electron acceleration
2.3 Particle dynamics in a non-uniform wave: the ponderomotive force (PF)
2.3.1 PF from a longitudinal plasma wave
2.3.2 PF from a transverse light wave
2.3.3 PF from the beat-wave between overlapped waves
2.3.4 Connection with the electron motion in a finite laser pulse
3 Propagation of light waves in plasmas
3.1 Propagation of light in plasmas
3.1.1 WKB description
3.1.2 Airy description at the turning point
3.1.3 Ray-tracing
3.1.4 Estimating collisional absorption in non-uniform plasma profiles using ray-tracing
3.1.5 Frequency shift of a light wave in a rarefaction profile (aka Dewandre effect)
3.2 Nonlinear self-action effects
3.2.1 Plasma response to a ponderomotive perturbation (kinetic vs. fluid)
3.2.2 The nonlinear refractive index of plasmas
3.2.3 Self-focusing: ponderomotive, relativistic, thermal
3.2.4 Self-guiding of a light pulse in plasma channels
3.2.5 Filamentation of a plane wave
3.2.6 Beam bending and other flowing plasma effects
4 Introduction to three-wave coupling instabilities in plasmas
4.1 Introduction to three-wave coupling instabilities
4.1.1 Physical picture; conservation of action and momentum (Manley-Rowe)
4.1.2 Exhaustive list of 3-wave coupling instabilities: primary vs. secondary processes
4.2 Derivation of the coupled mode equations
4.3 Spatial vs. temporal growth
4.3.1 Connection between temporal growth rate and spatial (convective) gain rate
4.3.2 The Rosenbluth gain formula for inhomogeneous plasmas
4.3.3 Absolute vs. convective instabilities
4.4 Impact of finite laser bandwidth on instabilities
4.5 Fluctuations and noise sources for instabilities
4.6 Polarization effects
5 Stimulated Brillouin scattering
5.1 Introduction, region of existence
5.2 Coupling coefficients:
5.2.1 Temporal growth rate
5.2.2 Transition from backward SBS to forward SBS to filamentation
5.2.3 Spatial gain in homogeneous vs. inhomogeneous plasmas
6 Crossed-beam energy transfer
6.1 Introduction, region of existence
6.2 Coupling coefficients
6.3 Polarization effects
6.4 Momentum deposition
6.5 Transient effects
7 Stimulated Raman scattering
7.1 Introduction, region of existence
7.2 Coupling coefficients:
7.2.1 Temporal growth rate
7.2.2 Spatial gain in homogeneous vs. inhomogeneous plasmas
7.3 Side- and forward-scatter
7.4 Production of supra-thermal electrons
8 Two-plasmon decay
8.1 Coupling coefficients:
8.1.1 Temporal growth rate
8.1.2 Spatial gain in homogeneous vs. inhomogeneous plasmas
8.2 Absolute instability threshold
8.3 Production of supra-thermal electrons
9 Saturation or inflation mechanisms of three-waves instabilities
9.1 Pump depletion
9.1.1 1D solution for homogeneous plasmas (aka the “Tang formula”)
9.1.2 2D solution for CBET
9.2 Kinetic effects
9.2.1 Particle trapping and nonlinear frequency shifts
9.2.2 Trapped particle instability
9.2.3 Super-Gaussian distributions (Langdon effect)
9.2.4 Stochastic heating; quasilinear theory
9.3 Secondary decay mechanisms
9.3.1 Langmuir decay instability
9.3.2 Two-ion decay instability
9.3.3 Re-scatter of backscatter
9.4 Plasma wave self-focusing and filamentation
9.5 Generation of harmonics
10 Anomalous absorption processes
10.1 Absorption by excitation of plasma waves
10.1.1 Resonant absorption
10.1.2 Two-plasmon decay & SRS
10.1.3 Non-Maxwellian distributions: Lagndon / Silin effects
10.2 Absorption via turbulence: return current instability
11 Optical smoothing of high-power lasers
11.1 Spatial smoothing
11.1.1 Random phase plates
11.1.2 Characteristics and statistical distribution of speckles
11.2 Temporal smoothing
11.2.1 Smoothing by spectral dispersion (SSD)
11.2.2 Speckle motion and LPI mitigation with SSD
11.3 Spatio-temporal smoothing: induced spatial incoherence (ISI)
11.4 Stimulated rotational Raman scattering
11.5 Polarization smoothing (PS)
11.5.1 Effect of PS on the speckle characteristics and statistical distribution
11.5.2 Mitigation of LPI from PS
11.6 LPI from optically smoothed beams
11.6.1 Impact of finite aperture and bandwidth on LPI
11.6.2 Filamentation of smoothed laser beams
11.6.3 Beam bending of smoothed beams
11.6.4 Independent speckles models for backscatter instabilities
12 Experimental techniques and diagnostics
12.1 Measurements of plasma conditions using Thomson scattering
12.2 Measurements of laser-plasma instabilities
12.2.1 Direct measurement of scattered light waves
12.2.2 Thomson-scattering off driven plasma waves
12.2.3 Measurement of Bremsstrahlung emission from suprathermal electrons
13 Applications of laser-plasma interactions
13.1 CBET in ICF experiments for symmetry tuning
13.2 Laser acceleration of electrons
13.2.1 Excitation of nonlinear plasma waves using a short-pulse laser
13.2.2 Relativistic acceleration of electrons in a laser wakefield accelerator (LFWA)
13.2.3 Limitations to LWFA
13.2.4 Plasma wakefield from self-modulation of a long-pulse laser
13.2.5 Betatron x-ray generation from laser-plasma-accelerated electrons
13.2.6 Direct laser acceleration
13.2.7 Ponderomotive heating of electrons in laser-solid interactions
13.3 Laser acceleration of ions
13.3.1 Target-normal sheath acceleration (TNSA)
13.3.2 “Mora” scaling of ion energy for TNSA
13.3.3 Radiation pressure acceleration (RPA)
13.4 Short pulse amplification using plasmas
13.4.1 The “pi-pulse” regime of nonlinear short-pulse amplification
13.5 Plasma photonics
14 Appendix
14.1 LPI formulary
14.2 Simulation models and techniques
