Relativistic electron beam transport for fast ignition relevant scenarios

A crucial issue surrounding the feasibility of fast ignition, an alternative inertial confinement fusion scheme, is the ability to efficiently couple energy from an incident short-pulse laser to a high-density, pre-compressed fuel core. Energy transfer will involve the generation and transport of a relativistic electron beam, which may be subject to a number of instabilities such as the two-stream, Weibel, and filamentary instabilities that act to inhibit energy transport. This research addressed these issues by investigating the three main phases of the electron transport process: hot electron generation in the cone and the extent of confinement along the cone surface, linear instability growth in the outer plasma corona, and the nonlinear saturated state in the inner plasma corona. Analytical and computational models were constructed to include relevant physics that had been excluded from previous models, such as kinetic and collisional effects, and included use of a sophisticated particle-in-cell code (LSP). During the initial phase of transport, our simulation results showed that contrary to experimental claims, hot electron surface confinement is only a minor effect and the cone target angle is a minimal concern for design considerations. The discrepancy was attributed to a phenomenon known as escaping electrons and the enhanced intensity of electrons measured along the surface was attributed to target geometry, rather than surface confinement.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Nuclear Science and Engineering.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2009

Author dc:creator

• Cottrill, Larissa A

Advisor dc:contributor.advisor

• Kim Molvig.

• Nuclear Science and Engineering.

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/1721.1/53262

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/53262