Bombardment of Thin Lithium Films With Energetic Plasma Flows

Here, we present experimental verification of substantially reduced target surface temperature with the use of thin lithium films on surface of the target as compared to a bare target. Furthermore, optical measurements are made to determine the density and temperature of the lithium vapor cloud as it expands away from the target surface. A collisional-radiative model for both neutrals and singly ionized lithium is used to model the lithium vapor and is found to correlate well with the optical measurements. The vapor cloud electron temperature is found to vary from 2--3 eV with peak heating occurring 3--5 mm away from the target. While the lithium neutral density is found to fall off exponentially from the surface, the lithium ion density is peaked 5--10 mm away from the target. This suggests an ionization front at this distance from the target where the energy from the incident plasma is primarily absorbed by the lithium vapor. It is estimated that the primary mechanisms for energy deposition into the lithium vapor are due to primary and secondary ionizations of the lithium as well as electron-lithium scattering. The energy absorbed by these processes correlates well with the energy reduction found to the target surface when a lithium coating is present.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Nuclear Engineering

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2015

Author dc:creator

• Gray, Travis Kelly

Contributors dc:contributor

• Ruzic, David N.

• Engineering, Nuclear

Language dc:language

eng

Identifier

(MiAaPQ)AAI3392026

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/85924