Helical Instability Evolution in Dynamic-Screw-Pinch-Driven Plasma Implosions

Regents Of The University Of Michigan - Ann Arbor, Ann Arbor MI

Investigators

Abstract

This award supports an effort to understand a plasma compression technique called the dynamic screw pinch, which has been demonstrated to reduce plasma instabilities. The knowledge gained in this project could enable more powerful x-ray generation, higher-pressure materials properties experiments, more efficient nuclear fusion generation, and a better understanding of astrophysical processes. The project will benefit society by advancing basic scientific knowledge, enabling future energy sources, and improving national defense capabilities. This project will also help train a diverse group of undergraduate and graduate students in plasma science and engineering while building stronger partnerships between academia, industry, and national laboratories. The project is awarded by the NSF Division of Physics with support from the National Nuclear Security Administration within the Department of Energy. This project will investigate the way in which cylindrical plasmas become unstable and break apart when they are strongly compressed by a magnetic field. Recently, a plasma compression technique called the dynamic screw pinch (DSP) has been demonstrated to reduce plasma instability growth in initially solid-metal thin-foil liner implosions on 1-MA, 100-nanosecond pulsed power facilities. The DSP technique uses a helical magnetic field with a time-dependent pitch angle to compress the cylindrical plasma. Despite the success of the DSP technique, questions remain as to how DSP-driven instabilities initially form and evolve relative to those driven by a standard z-pinch with a purely azimuthal magnetic field. This project will evaluate competing theories computationally and experimentally. Specifically, this project will investigate the roles of the electrothermal instability, coronal plasma dynamics, and magnetic field pitch angles in the seeding and evolution of the magneto-Rayleigh-Taylor instability (MRTI). This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.