Theory and simulations of nonlinear and inelastic processes in relativistic laser plasma interactions [Elektronische Ressource] / vorgelegt von Anupam Karmakar

Sujets

• Physik

Informations

• Publié par: heinrich-heine-universitat_dusseldorf
• Publié le: 01 janvier 2008
• Nombre de lectures: 37
• Langue: English
• Poids de l'ouvrage: 8 Mo

Extrait

Theory and Simulations of Nonlinear
and Inelastic Processes in Relativistic
Laser Plasma Interactions
Inaugural-Dissertation
zur
Erlangung des Doktorgrades der
Mathematisch-Naturwissenschaftlichen Fakultät
der Heinrich-Heine-Universität Düsseldorf
vorgelegt von
Anupam Karmakar
aus Burdwan, Indien
Düsseldorf
Mai, 2008Aus dem Institut für theoretische Physik I
der Heinrich-Heine-Universität Düsseldorf
GedrucktmitderGenehmigungderMathematisch-NaturwissenschaftlichenFakultätder
Heinrich-Heine-Universität Düsseldorf
Referent: Prof. Dr. Alexander Pukhov
Korreferent: Prof. Dr. K. H. Spatschek
Tag der mündlichen Prüfung: 30. 06. 2008Theory and Simulations of Nonlinear
and Inelastic Processes in Relativistic
Laser Plasma Interactions
Anupam Karmakar
May, 2008
Institute for Theoretical Physics I
Heinrich-Heine University
Düsseldorf, Germany4"To raise new questions, new possibilities, to regard old questions from a new angle,
requires creative imagination and marks real advances in science."
– Albert Einstein6Dedicated to my parents Mr. Phanibhusan Karmakar and Mrs. Sonali Karmakar,
the reason of my existence and the supreme support of my life.8Contents
1 Introduction 11
1.1 Laser Plasma Interaction Physics : Motivation . . . . . . . . . . . . . . . 11
1.2 Thesis Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
1.3 A Brief Historical Overview . . . . . . . . . . . . . . . . . . . . . . . . . 13
1.3.1 Plasma based particle acceleration . . . . . . . . . . . . . . . . . 13
1.3.2 Advanced numerical methods for simulations . . . . . . . . . . . . 14
1.3.3 Relativistic electron beam propagation . . . . . . . . . . . . . . . 15
1.4 Basic Laser-Plasma Interaction Physics . . . . . . . . . . . . . . . . . . . 16
1.4.1 Optical field ionization . . . . . . . . . . . . . . . . . . . . . . . . 16
1.4.2 Plasma frequency and Debye length . . . . . . . . . . . . . . . . . 19
1.4.3 Particle motion in an electromagnetic wave, relativistic threshold 20
1.4.4 P Acceleration Mechanisms . . . . . . . . . . . . . . . . . . 24
1.4.5 Weibel and Two-stream Instability . . . . . . . . . . . . . . . . . 28
2 Acceleration of Electrons Using Ionization 33
2.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
2.2 Implementation of Tunneling Ionization in VLPL Code . . . . . . . . . . 33
2.3 Collimated Attosecond GeV Electron Bunches . . . . . . . . . . . . . . . 36
2.3.1 Electron acceleration from ionization of high-Z material . . . . . . 37
2.3.2 Radially polarized laser pulse . . . . . . . . . . . . . . . . . . . . 37
2.3.3 Single-cycle laser pulse . . . . . . . . . . . . . . . . . . . . . . . . 41
2.3.4 Acceleration by the Gaussian beam . . . . . . . . . . . . . . . . . 43
2.3.5 Theoretical explanation . . . . . . . . . . . . . . . . . . . . . . . 43
2.4 Hot Electron Production from Laser Irradiated Polystyrene Spheres . . . 45
2.4.1 Simulation of the Texas laser droplet interaction experiment . . . 45
2.5 Conclusion and Outlook . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
3 Collisions in Relativistic Laser-Plasma Interactions 51
3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
3.2 Numerical Simulation of Electron-Ion Binary Collisions . . . . . . . . . . 51
3.2.1 Implementation of the VLPL3d collision module . . . . . . . . . . 52
3.3 Benchmarking with Physical Processes . . . . . . . . . . . . . . . . . . . 55
3.3.1 Scattering of hot electron beam in ambient collisional plasma . . . 55
3.4 Directed Acceleration of Electrons from Solid Surface . . . . . . . . . . . 57
3.4.1 3D–PIC simulation of the experiment . . . . . . . . . . . . . . . . 58
3.5 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
9Contents
4 Implicit PIC-Hydrodynamic Hybrid Simulation Code H-VLPL 67
4.1 Introduction: Motivation . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
4.2 The Hybrid Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
4.3 The Numerical Algorithm of H-VLPL . . . . . . . . . . . . . . . . . . . . 70
4.4 Numerical Dispersion and Stability . . . . . . . . . . . . . . . . . . . . . 75
4.4.1 Dispersion relation for the x-component . . . . . . . . . . . . . . 75
4.4.2 Disp for the y- and the z-component . . . . . . . . 76
4.5 Benchmarking with Physical Processes . . . . . . . . . . . . . . . . . . . 79
4.5.1 Reflection and refraction of incident pulse . . . . . . . . . . . . . 80
4.5.2 Energy conservation . . . . . . . . . . . . . . . . . . . . . . . . . 80
4.5.3 Acceleration of ions from a target back surface (TNSA) . . . . . . 82
4.5.4 Scaling of the skin fields . . . . . . . . . . . . . . . . . . . . . . . 84
4.5.5 Collisional absorption . . . . . . . . . . . . . . . . . . . . . . . . . 86
4.6 Conclusions and Outlook . . . . . . . . . . . . . . . . . . . . . . . . . . . 87
5 Effects of Temperature and Collisions on the Weibel Instability 89
5.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89
5.2 Different Simulation Geometries . . . . . . . . . . . . . . . . . . . . . . . 90
5.3 Details of the PIC Simulation Parameters . . . . . . . . . . . . . . . . . 92
5.4 Simulation Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92
5.4.1 Transverse geometry . . . . . . . . . . . . . . . . . . . . . . . . . 92
5.4.2 Longitudinal . . . . . . . . . . . . . . . . . . . . . . . . 98
5.4.3 Full 3D simulations . . . . . . . . . . . . . . . . . . . . . . . . . . 104
5.5 Analytical Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105
5.6 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110
6 Conclusion 111
Appendix 113
A Particle-in-cell (PIC) Simulation Codes 113
A.1 The Basic Equations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113
A.2 The Code VLPL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115
References 117
Index 137
10