DOE OSTI2016
Pulsed high-power technology is used to create MHD-governed, dynamically-evolving, plasma-filled magnetic flux tubes. Advanced diagnostics measure the dynamical evolution and the measurements are then related to theoretical models. The dynamics are relevant to solar coronal plasma loops, astrophysical jets, and other situations where magnetic field lines intercept a boundary and current flows from the boundary into the plasma along the field lines. The morphology is time-dependent and determined by complex physics involving magnetic forces, hydrodynamic forces, and boundary conditions. Unlike magnetic fusion plasma experiments which are in approximate MHD equilibrium, fast accelerated plasma flows are a dominant feature. Typical parameters are: electric current 50-150 kA, applied voltage 3-6 kV, magnetic field 0.3 to 3 kG, experiment duration 10 μs, jet velocity 10’s of km/s, flux tube dimensions a few cm in radius and 10’s of cm in length. A scheme for measuring the wavelength of a quasi-neutral magnetic plasma wave using a single point of measurement was demonstrated both by an actual spacecraft (MMS) and in the lab. The experimental work is supported by a strong theoretical component. Theoretical activities included proposing a model for driving astrophysical jets (model motivated by lab experiments), and providing new insights into fast collisionless magnetic reconnection by demonstration of a new, more fundamental parameter than previously used.
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