Investigation and characterization of single hot spot laser-plasma interactions

Control of parametric laser-plasma interactions (LPI) is essential to the success of inertial confinement fusion (ICF). Through a research collaboration with the Los Alamos National Laboratory (LANL), we have had the opportunity to participate in world-class laser-plasma experiments. The goal of these experiments was to gain a fundamental understanding of LPI by studying the interaction of a single laser hot spot, or speckle, with a preformed, quasi-homogeneous, long scale-length plasma. Recent single hot spot experiments resulted in a wealth of data and the first definitive observation of two LPIs. Namely, the Langmuir decay instability (LDI) cascade and stimulated scattering off of an acoustic-like electron mode below the usual electron plasma wave frequency. The LDI is the result of the electron plasma wave (EPW) generated by stimulated Raman scattering (SRS) growing to a sufficient amplitude such that it exceeds a threshold (proportional to the damping of the LDI daughter waves) and undergoes parametric decay into another counter-propagating EPW and a co-propagating ion acoustic wave (IAW). Subsequent EPW decays due to LDI are possible and collectively more than one EPW generated by LDI is called LDI cascade. The LDI cascade can play a role in the saturation of SRS since wave energy from the SRS EPW couples into secondary waves that are non-resonant with the SRS process. Stimulated scattering from an electrostatic wave at a frequency and phase velocity (co 0.4cpe, vl1.4ve) between that of an EPW and LAW was also observed.

Department dc:contributor.department

Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2002

Author dc:creator

• Focia, Ronald J

Advisor dc:contributor.advisor

• Abraham Bers and Juan C. Fernández.

• Electrical Engineering and Computer Science.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/87171

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/87171