Vlasov–Maxwell simulations of backward Raman amplification of seed pulses in plasmas
| Autor: | Magdi Shoucri, Bedros Afeyan |
|---|---|
| Rok vydání: | 2016 |
| Předmět: |
Physics
Raman amplification Scattering Waves in plasmas Forward scatter business.industry Electron Condensed Matter Physics 01 natural sciences Atomic and Molecular Physics and Optics 010305 fluids & plasmas Pulse (physics) symbols.namesake Optics 0103 physical sciences symbols Electrical and Electronic Engineering Atomic physics 010306 general physics business Raman scattering Envelope (waves) |
| Zdroj: | Laser and Particle Beams. 34:576-600 |
| ISSN: | 1469-803X 0263-0346 |
| Popis: | We study the problem of the amplification of an ultra-short seed pulse via stimulated Raman backscattering (SRB) from a long pump pulse (assumed to have an envelope with a constant amplitude), in an underdense plasma. The SRB interaction couples the pump light wave to a daughter light seed wave propagating in the opposite direction, scattered off an electron plasma wave. In recent numerical simulations, it has been observed that besides stimulated Raman backward scattering (SRBS) and stimulated Raman forward scattering, other high-frequency kinetic instabilities can occur when modified distribution functions exist during the evolution of the system. In particular, we showed the prominent role played by kinetic electrostatic electron nonlinear (KEEN) waves (Afeyan et al., 2004). We continue this work by applying a relativistic Vlasov–Maxwell code to study stimulated KEEN wave scattering (SKEENS) and its role in the SRBS short pulse amplification processes. An analysis of the full spectrum of waves participating in the amplification processes is presented. The absence of spurious noise in grid-based Vlasov codes allows us to follow the evolution of the system with a kinetic (collisionless) description. This affords us a glimpse at the intricate phase-space structures such as trapped particle orbits, which coexist and interact nonlinearly in the electron distribution function. |
| Databáze: | OpenAIRE |
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