Natural fueling of a tokamak fusion reactor

• Published in: Physics of plasmas 2010-04, Vol.17 (4), p.040701-040701-4
• Main Authors: Wan, Weigang, Parker, Scott E., Chen, Yang, Perkins, Francis W.
• Format: Article
• Language: English
• ISSN: 1070-664X; 1089-7674
• DOI: 10.1063/1.3389225

A natural fueling mechanism that helps to maintain the main core deuterium and tritium (DT) density profiles in a tokamak fusion reactor is presented. In H -mode plasmas dominated by ion-temperature gradient (ITG) driven turbulence, cold DT ions near the edge will naturally pinch radially inward toward the core. This mechanism is due to the quasineutral heat flux dominated nature of ITG turbulence and still applies when trapped and passing kinetic electron effects are included. Fueling using shallow pellet injection is augmented by an inward pinch of cold DT fuel. The natural fueling mechanism is investigated using the gyrokinetic turbulence code GEM [ Y. Chen and S. E. Parker , J. Comput. Phys. 220 , 839 ( 2007 ) ] and is analyzed using quasilinear theory. Profiles similar to those used for conservative International Thermonuclear Experimental Reactor [ R. Aymar , Nucl. Fusion 41 , 1301 ( 2001 ) ] transport modeling that have a completely flat density profile are examined and it is found that natural fueling actually reduces the linear growth rate and energy transport. Natural fueling requires a two-component plasma and ion-ion and charge-exchange collisions set limits on this favorable effect.