[PAST EVENT] Physics Colloquium

November 4, 2011
4pm - 5pm
Small Hall, Room 111
300 Ukrop Way
Williamsburg, VA 23185Map this location
Abstract: One of the main challenges for the future is to provide clean energy (=electricity) to accommodate our growing world population with enough electricity to improve living conditions in 3rd world countries and continue our high quality living standards in the developed world. One very promising technique to produce electricity on a large scale is nuclear fusion. In this talk, I will discuss some of the current issues in Tokamak research concerning nuclear fusion. One of the main challenges in Tokamak research is containing a plasma hotter than the sun, while limiting the heat fluxes to the vessel walls.
A few years ago, at the DIII-D Tokamak facility, a new technique was discovered to reduce the size and completely eliminate edge localized mode, with resonant magnetic perturbations (RMPs). RMPs reduce the edge pedestal pressure gradient below the peeling-ballooning stability limit in part by increasing particle transport and reducing the density by 5%-30% [1]. In this talk, to better understand the effects of RMP on particle transport, we present the first direct measurements of the perturbed diffusion and outward pinch velocity. We show that the perturbed pinch decreases and the diffusion increases. Using a 2D fluid code, we interpret what this means for how the background particle transport changes. Finally we connect this to the changes in turbulent particle transport.

[1] P.B. Snyder, et al., Nucl. Fusion 47 (2007) 961.