Electrical and Computer Engineering ETDs

Publication Date

10-17-1995

Abstract

The International Thermonuclear Experimental Reactor program (ITER) is a world wide collaboration to design and build the first new large scale tokamak fusion reactor of the 21st century. Under certain operating conditions the highly energetic plasma contained within a tokamak can become unstable and result in a loss of magnetic confinement, allowing the plasma to strike the interior of the vacuum chamber and cause damage. This event is known as a disruption. Plasma Facing Component (PFC) materials protect the interior of the tokamak from damage in the event of a disruption. Complex scaling laws have been used to estimate the expected disruption plasma parameters in ITER. Small-scale simulations of disruption events are used to evaluate PFC candidate materials. The results of these simulations are used to validate computer codes written to predict performance of PFC materials over the full range of disruption energy densities expected in the ITER tokamak. A better understanding of the plasmas produced in disruption simulators enables plasma modelers to refine PFC erosion prediction codes. Tokamak disruption simulation experiments have been conducted at the University of New Mexico using the PLADIS I plasma gun system. A variety of plasma diagnostics have been used to investigate the characteristics of a simulated tokamak disruption. These diagnostics have included emission spectroscopy in the optical and Vacuum Ultra Violet (VUV) regimes, two-color pyrometry, interferometry and other methods to quantify the incident and vapor shield plasmas of a simulated tokamak disruption. Taken separately, each of the results from these diagnostics is significant but does not provide a complete picture of the interaction between the surface and the plasma. The synthesis of beam area measurements using laser interferometry, damage targets and other methods is used to determine the radial structure of the plasma beam. The synthesis of results from surface pressure and surface temperature measurements is used to determine the dynamics of the formation of the vapor shield plasma. The synthesis of results from VUV spectroscopy and two color pyrometry is used to determine the vertical extent, internal structure and minimum electron temperature of the vapor shield plasma.

Document Type

Dissertation

Language

English

Degree Name

Electrical Engineering

Level of Degree

Doctoral

Department Name

Electrical and Computer Engineering

First Committee Member (Chair)

John M. Gahl

Second Committee Member

Paul D. Rockett

Third Committee Member

John R. McNeil

Fourth Committee Member

Charles Fleddermann

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