Influence of realistic plasma density profile and laser shape on the SBS amplification

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Table of contents

1 Introduction and basic notions of laser-plasma interactions 
1.1 Laser Plasma Interaction
1.2 The Propagation of Light in a Plasma
1.3 Plasma waves
1.3.1 Electron plasma waves
1.3.2 Ion acoustic waves
1.4 Stimulated Brillouin and Raman scattering
1.4.1 Stimulated Brillouin Backscattering
1.4.2 Stimulated Raman Backscattering
2 Energy flow directionality and time scale characterization in the strong coupling regime for SBS 
2.1 Weak coupling regime
2.2 Strong coupling regime
2.3 Different phases of the amplification in the strong-coupling limit
2.3.1 Initial seed growth
2.3.2 Exponential growth – ’Linear’ phase
2.3.3 Pump depletion and growth saturation
2.4 Conclusions
3 Intrinsic frequency chirp in the strong coupling regime for SBS 
3.1 Effect of the chirp on the coupling
3.2 Influence of the plasma density shape and laser intensity profile on the phase evolution
3.2.1 Phase evolution for the propagation of pump and seed lasers without coupling
3.2.2 The role of a plasma density shape on the phase evolution
3.2.3 Density profile with n0(^x = 0) == 0
3.2.4 Density profile with n0(^x = 0) = 0
3.2.5 Intrinsic frequency chirp due to a inhomogeneous plasma density profile
3.2.6 Influence of realistic plasma density profile and laser shape on the SBS amplification
3.3 Conclusions
4 Parametric studies of sc-SBS optimal coupling via one-dimensionalPIC simulations 
4.1 Simulations set-up
4.2 Shape of the density profile
4.3 Relative delay between the pump and seed laser pulses
4.4 Initial seed duration
4.5 Energy transfer and final duration of the seed
4.6 Conclusions
5 Recent experiments on strong coupling SBS amplification and comparison with one dimensional PIC simulations 
5.1 Experiments and simulations comparison
5.1.1 Comparison between spectra of the amplified seed from simulations and experiments
5.1.2 Influence of amplification on SRS spectra
5.2 Conclusions
6 Presentation of the new particle in code SMILEI and results of two dimensional simulations of sc-SBS amplification 
6.1 The Particle-In-Cell (PIC) method for collisionless plasmas
6.1.1 The PIC loop
6.2 Two dimensional simulation of sc-SBS amplification of a short laser pulse
6.2.1 Simulations set-up
6.2.2 Amplification results
6.3 Conclusions
Conclusions
Communications related to this thesis 
Appendices 
A Relation between the chirp parameter and the duration of a gaussian laser beam 
B SMILEI’s performance and capabilities 
Bibliography