Event
Ph.D. Dissertation Defense: Sung Jun Yoon
Tuesday, March 25, 2014
10:00 a.m.
IREAP building, Room 1207 (ERF 1207)
Maria Hoo
301 405 3681
mch@umd.edu
ANNOUNCEMENT: Ph.D. Dissertation Defense
Professor Howard M. Milchberg, Chair/Advisor
Professor Phillip Sprangle
Professor Julius Goldhar
Dr. John P. Palastro
Professor Konstantinos D. Papadopoulos, Dean's Representative
Corrugated plasma waveguides can be generated by the interaction between an ionizing laser pulse and an atomic cluster flow interrupted by an array of thin wires,. When the collisional mean free path of the clusters is greater than the wire diameter, shadows of the periodically located wires are imparted on the cluster flow, leading to the production of axially modulated plasma waveguides after laser heating of the flow. This occurs when the population ratio of clusters to monomers in the gas is high. At other limit, dominated by gas monomer flow, shock waves generated off the wires by the supersonic gas flow disrupts modulated waveguide generation.
Lastly, we experimentally demonstrate LWFA with ionization injection in a N5+ plasma waveguide. It is first shown that the plasma waveguide is almost completely composed of He-like nitrogen (N5+).It is then shown that intense pulse channeling in the plasma waveguide drives stronger wakefields, while the ionization injection process is critical to lowering the laser intensity threshold for self-trapping.