Modeling Non-Linear Plasma-Wave Interaction at the Edge of a Tokamak PlasmaO. Meneghini, S. Shiraiwa, and C. Lau
Massachusetts Institute of Technology
High power Lower-Hybrid RF waves injected at in a Tokamak plasma can strongly modify the edge plasma. This is caused by ponderomotive forces pushing charged particles in an inhomogeneous oscillating electromagnetic field towards weaker field areas. On the Alcator C-Mod Tokamak, edge density profile measurements by means of an X-mode SOL reflectometer were able for the first time to accurately document the density depletion profile in the presence of high power (>1MW/m2) LH-RF.
The measurements were well reproduced by means of a fullwave COMSOL simulation in which the density depletion is self-consistently taken into account via an iterative approach. This model was verified in 1-D and has been extended to model arbitrary 2-D or 3-D geometries.