Electrical and Computer Engineering ETDs

Publication Date

Summer 7-28-2026

Abstract

Sandia's refurbished $Z$-pinch machine experiences persistent current loss in its post-hole convolute and inner magnetically insulated transmission line regions, widely attributed to low-density electrode plasmas whose formation and transport remain poorly constrained by existing diagnostics. This dissertation develops and validates a fiber-coupled, continuous-wave, second-harmonic orthogonally polarized dispersion interferometer for time-resolved measurements of electron areal density in millimeter-scale gaps. The diagnostic employs single-laser second-harmonic generation, non-steering differential phase control, and polarization-based phase retrieval to achieve sub-$10^{15}$~cm$^{-2}$ sensitivity, multi-hundred-megahertz bandwidth, and sub-$200$~$\mu$m effective cross-gap spatial resolution. Performance is benchmarked against a $94$~GHz interferometer on the UNM Helicon-Cathode plasma device and then fielded on the Mykonos pulsed-power driver using $Z$R-relevant parallel-plate hardware. The resulting $\langle n_{e} \, L \rangle(t)$ measurements constrain low-density electrode plasma formation and transport mechanisms relevant to MITL current-loss physics.

Keywords

Dispersion Interferometer, Optical Interferometry, Plasma Physics, Pulsed Power, Magnetically Insulated Transmission Line (MITL), Current Loss

Project Sponsors

Sandia National Laboratories

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 Schamiloglu

Third Committee Member

Ryan McBride

Fourth Committee Member

Jens Schwarz

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