Bulletin of the American Physical Society
63rd Annual Meeting of the APS Division of Plasma Physics
Volume 66, Number 13
Monday–Friday, November 8–12, 2021; Pittsburgh, PA
Session QI02: HED/ICF/MFE: Thermonuclear Burn
3:00 PM–5:00 PM,
Wednesday, November 10, 2021
Room: Ballroom C
Chair: Uri Shumlak, University of Washington
Abstract: QI02.00004 : Theoretical interpretation of the operational density limit and comparison to experimental data
4:30 PM–5:00 PM
(Ecole Polytechnique Federale de Lausanne)
Three-dimensional turbulent simulations carried out by using the GBS code have pointed out the presence of a regime of degraded confinement at high values of collisionality and low values of heat source . This regime, characterized by a large turbulent transport driven by resistive ballooning modes, has been associated to the crossing of the density limit. By leveraging these simulation results, a theory-based scaling law of the crossing of the density limit has been derived. While the theoretical scaling law shares with the Greenwald density limit the main dependences on the plasma current and tokamak minor radius, it also shows a significant dependence on the power crossing the separatrix.
The scaling law derived in this work has been validated against experimental data taken within a multi-machine effort involving ASDEX Upgrade, JET and TCV tokamaks. This database is composed also of discharges that use advanced active control techniques that avoid the disruption after the onset of the MARFE as the density limit is approached. Therefore, the edge density was measured near the onset of the MARFE with a very high time resolution, allowing for an accurate comparison to the theoretical predictions. The predicted value of the density limit shows a remarkable good agreement with the density measured at the onset of the MARFE.
 Giacomin & Ricci, J Plasma Phys (2020)
The American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics.
1 Physics Ellipse, College Park, MD 20740-3844
Editorial Office 1 Research Road, Ridge, NY 11961-2701 (631) 591-4000
Office of Public Affairs 529 14th St NW, Suite 1050, Washington, D.C. 20045-2001 (202) 662-8700