Rayleigh—Taylor-Instability Evolution in Colliding-Plasma-Jet Experiments with Magnetic and Viscous Stabilization

The Rayleigh—Taylor instability causes mixing in plasmas throughout the universe, from micron-scale plasmas in inertial confinement fusion implosions to parsec-scale supernova remnants. The evolution of this interchange instability in a plasma is influenced by the presence of viscosity and magnetic fields, both of which have the potential to stabilize short-wavelength modes. Very few experimental observations of Rayleigh—Taylor growth in plasmas with stabilizing mechanisms are reported in the literature, and those that are reported are in sub-millimeter scale plasmas that are difficult to diagnose. Experimental observations in well-characterized plasmas are important for validation of computational models used to make design predictions for inertial confinement fusion efforts. This dissertation presents observations of instability growth during the interaction between a high Mach-number, initially unmagnetized plasma jet and a stagnated, magnetized plasma. A multi-frame fast camera captures Rayleigh—Taylor-instability growth while interferometry, spectroscopy, photodiode, and magnetic probe diagnostics are employed to estimate plasma parameters in the vicinity of the collision. As the instability grows, an evolution to longer mode wavelength is observed. Comparisons of experimental data with idealized magnetohydrodynamic simulations including a physical viscosity model suggest that the observed instability evolution is consistent with both magnetic and viscous stabilization. These data provide the opportunity to benchmark computational models used in astrophysics and fusion research.

Name thesis:degree_name

Electrical Engineering

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Electrical and Computer Engineering

Year

2015

Author dc:creator

• Adams, Colin Stuart

Contributors dc:contributor

• Gilmore, Mark
• Schamiloglu, Edl
• Pihlstrom, Ylva
• Hsu, Scott

• Plasma Physics
• Raleigh--Taylor Instability

Language dc:language

English

Repository record dc:identifier

https://digitalrepository.unm.edu/ece_etds/4

OAI identifier oai:identifier

oai:digitalrepository.unm.edu:ece_etds-1003