Electrical and Computer Engineering ETDs

Publication Date

Fall 11-14-2016

Abstract

Numerous solar and astrophysical observations of jet- and bubble-like plasma structures exhibit morphological similarities, suggesting that there may be common plasma physics at work in the formation and evolution processes of these structures at different system scales. The ideal magnetohydrodynamics (MHD) provide the necessary theoretical basis for employing laboratory experiments to investigate key physical processes in nonlinear astrophysical and solar systems, especially when magnetic fields are present.

A coaxial magnetized plasma gun has been designed, installed, and operated in the HelCat linear device at the University of New Mexico. In Region I, a current-driven plasma jet is formed. The plasma column experiences the current-driven kink instability consistent with the Kruskal-Shafranov criterion. When a perpendicular background magnetic field is applied, the jet column length increases with a longer lifetime and appears to show greater stability. Evidence suggests that magnetic tension, caused by the curvature of background magnetic field, leads to an axial sheared flow, which contributes to the stabilization. The calculated results are accordant with the stabilization criterion - reported by other research groups for similar magnetic geometrics.

In Region II, spheromak-like plasma formation is verified. When the spheromak plasma propagates into the background magnetic field, the typical self-closed magnetic configuration does not hold anymore. At the upper-side, the Rayleigh -Taylor instability has been observed. The theoretical analysis is present and the instability growth rate has been calculated.

Keywords

astrophysics, solar, plasma gun, axial sheared flow, kink instability, magnetic Rayleigh-Taylor instability

Document Type

Dissertation

Language

English

Degree Name

Electrical Engineering

Level of Degree

Doctoral

Department Name

Electrical and Computer Engineering

First Committee Member (Chair)

Mark Gilmore

Second Committee Member

Edl Schamilogu

Third Committee Member

Scott Hsu

Fourth Committee Member

Ylva M Pihlstrom

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