Introduction to Laser-Plasma Interactions

ISBN-13: 9783031234231 / Angielski / Twarda / 2023

Pierre Michel

Opis

This 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.

Spis treści

1.1   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

 

O autorze

Pierre Michel received his Ph.D. in physics from the Ecole Polytechnique in Paris in 2003, where he worked on experiment and modeling of long-pulse laser-plasma interactions. From 2004 to 2006 he was a postdoctoral Fellow at Lawrence Berkeley Laboratory, working in the BELLA Center on laser wakefield acceleration and laser-plasma-based ultra-short x-ray sources. He has been at Lawrence Livermore National Laboratory (LLNL) since 2006, where he is a group leader for laser-plasma interaction (LPI) physics in the National Ignition Facility Directorate and has been the principal investigator on several projects on plasma- and gas-optics. He is a visiting scientist at the University of California, Berkeley, and has taught online lectures on LPI through the LLNL High Energy Density Center. He has published over a hundred papers on short- and long-pulse LPI, is a recipient of the Edouard Fabre Prize (European Physical Society), the John Dawson Award for Excellence in Plasma Physics (American Physical Society) and is a Fellow of the American Physical Society.