Michael Van Zeeland

Nonlinear hybrid simulation of internal kink with beam ion effects in DIII-D

In DIII-D sawteething plasmas, long-lived (1,1) kink modes are often observed between sawtooth crashes. The saturated kink modes have two distinct frequencies. The mode with higher frequency transits to a fishbone-like mode with sufficient on-axis neutral beam power. In this work, hybrid simulations with the global kinetic-magnetohydrodynamic (MHD) hybrid code M3D-K have been carried out to investigate the linear stability and nonlinear dynamics of the n = 1 mode with effects of energetic beam ions for a typical DIII-D discharge where both saturated kink mode and fishbone were observed. Linear simulation results show that the n = 1 internal kink mode is unstable in MHD limit. However, with kinetic effects of beam ions, a fishbone-like mode is excited with mode frequency about a few kHz depending on beam pressure profile. The mode frequency is higher at higher beam power and/or narrower radial profile consistent with the experimental observation. Nonlinear simulations have been performed to investigate mod...

Keeping fusion plasmas hot

Interactions between electromagnetic waves and the most energetic ions in a plasma can perturb the orbits of those ions enough to expel them from the confining magnetic field.

Measurement and simulation of passive fast-ion D-alpha emission from the DIII-D tokamak

Author(s): Bolte, NG; Heidbrink, WW; Pace, D; Van Zeeland, M; Chen, X | Abstract:

Plasma density measurement using a dispersion interferometer based on second-harmonic generation in orientation-patterned GaAs

A dispersion interferometer based on second-harmonic generation in orientation-patterned GaAs has been used to measure the line density of electrons in a radio-frequency plasma with a detection limit of 7 × 10¹⁶ m^-2.