Fundamental Processes in Plasmas

University Of California-San Diego, La Jolla CA

Investigators

Abstract

Fundamental Processes in Plasmas T.M. O'Neil, C.F. Driscoll and D.H.E. Dubin This collaboration of 3 UCSD faculty will address a broad range of fundamental processes in plasmas, and will emphasize problems for which precise experimental tests of theory can be obtained. The experiments will be performed on camera-diagnosed pure-electron plasmas and laser-diagnosed pure-ion plasmas. The research will include work in 6 general areas: 1) Theory work on anti-hydrogen formation and relaxation via plasma collisions will continue, ranging from O'Neil's "Guiding Center Atom" regime to the more deeply-bound chaotic regimes. 2) Experiments have now measured the Salpeter enhancement of perp-to-parallel collisions in strongly correlated plasmas, and future work will quantitatively test theory ideas and apply them to "burn-front" propagation dynamics. 3) Experiments and theory on long-range ExB drift interactions will continue, characterizing heat transport, viscosity, and particle transport limited by background shear flows, utilizing laser-tagging to image the elusive thermally-excited convection cells. 4) Experiments will quantify the wave-coherent particle distribution function in the novel "Electron Acoustic Mode", with theory support to understand the extreme frequency-variability of these nonlinear waves. 5) Experiments and theory will continue on 2D fluid vortex dynamics, inviscid wave damping, and "vortex crystals," including statistical mechanics descriptions of these novel states. 6) Experiments and theory will develop the new "chaotic scattering" regime of neoclassical transport, which occurs when theta-rippled trapping separatrices are driven by plasma rotation. This work may be "transformative", given the broad range of wave damping, nonlinear wave coupling, and particle transport effects which are being observed and analyzed. This research environment is ideal for graduate student and post-doctoral training. The research has strong interdisciplinary connections with atomic physics, fluid dynamics, and statistical mechanics, as well as relevance to fusion plasmas. This research is also funded by DoE under a separate award under the NSF-DoE Partnership in Plasma Science and Engineering joint solicitation.