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epr_13_krstic_p-1.pdf2013-03-05 12:09:32Predrag Krstic


Author: Predrag S Krstic
Requested Type: Consider for Invited
Submitted: 2013-01-16 17:58:21


Contact Info:
Joint Institute of Computational Sciences, Univers
Oak Ridge National Lanboratory
Oak Ridge, Tennessee   37831-6

Abstract Text:
Plasma-Material Interface (PMI) mixes materials of the two worlds, creating in between a new entity, a dynamical surface which communicates between the two, creating one of the most challenging areas of multidisciplinary science, which has many fundamental processes and synergies. One of the largest technical challenges to the advancement of thermonuclear magnetic fusion energy is the erosion lifetime, thermo-mechanical and neutron damage of the reactor containment walls exposed to the fusion plasma.

How to build an effective science for PMI? How to build an integrated theoretical-experimental approach? The traditional trial-and-error approach to PMI for future fusion devices by successively refitting the walls of toroidal plasma devices with different materials and component designs is becoming prohibitively slow and costly. Since erosion, sputtering, retention, redeposition, reflection, displacement, etc. originate from atomic processes at nanoscale we seek to construct the PMI science from the bottom up, using atomistic approaches, recognizing its multi-scale character and building from the shortest, atomic, to the longest time and spatial scales.

The traditional trial-and-error approach to developing first-wall material and component solutions for future fusion devices is becoming prohibitively costly because of the increasing device size, curved toroidal geometry, access restrictions, and complex programmatic priorities. For this reason, the importance of developing computational models to extrapolate and optimize designs is increasingly being recognized. These computational models, validated by experiment, provide understanding of fundamental physical and chemical mechanisms and permit extrapolation to the realistic conditions of next-generation machines, providing predictive power for optimal material design of the large DEMO and FSNF machines.

Moreover, the behavior and confinement of the plasma fuel (hydrogen and its isotopes) is intrinsically dependent on the plasma-wall interface, among other factors. Manipulating magnetically-confined plasmas with hundred-nanometer low-Z wall coatings has been successful for many years, and in particular with lithium as manifested in nearly a dozen metallic and graphite-based tokamak fusion machines around the world. Plasmas in these complex tokamak fusion devices have characteristic lengths of a few centimeters to meters. It seems surprising that an ultra-thin low-Z film could have any effect on a plasma, which is five to seven orders in magnitude larger than the film, thus solidifying the idea of tuning fusion plasma behavior at nanoscale plasma-material interface.

Characterization: 2.0


University of Texas

Workshop on Exploratory Topics in Plasma and Fusion Research (EPR2013)
February 12-15, 2013
Fort Worth, Texas

EPR 2013