Impact of β n and Spectrum of n = 1 Applied Fields on Fast ion Losses in DIII-D
|Author/s||Gage, K. R.
Van Zeeland, M.
Heidbrink, W. W.
Pace, D. C.
Galdón Quiroga, Joaquín
García Muñoz, Manuel
|Department||Universidad de Sevilla. Departamento de Física Atómica, Molecular y Nuclear|
|Abstract||The effect of n = 1 magnetic perturbations (MPs) on prompt fast ion losses in DIII-D has been investigated using the light ion beam probe technique. The effect of normalized beta, β n, and the plasma response to the MPs ...
The effect of n = 1 magnetic perturbations (MPs) on prompt fast ion losses in DIII-D has been investigated using the light ion beam probe technique. The effect of normalized beta, β n, and the plasma response to the MPs is studied for several MP spectra. Magnetics data show a strong dependence of plasma response to β n that depends on the phase difference in perturbation coils, Δ ϕ U L . For most phases, the response increases with β n, however, the response is suppressed for phases between 180∘ and 240∘. Experimental data from scintillator based fast ion loss detectors shows that relative fluctuation of lost ions (20%-30% of the steady signal) does not diminish across the L- to H-mode transition for Δ ϕ U L = 240 ∘ , despite the 34% decrease in radial response field and 50% decrease in poloidal response field. Simulations of the DIII-D discharges using M3D-C1 and ASCOT5 find that prompt losses from neutral beam injection in each investigated case hit the first wall at several concentrated locations: the vessel floor, midplane diagnostic ports, vessel ceiling, and inner wall. Simulated losses from co-injection neutral beams are born outside the last closed flux surface, corresponding to radial orbit displacements of 3-6 cm due to the MPs.
|Funding agencies||Department of Energy. United States
Ministerio de Ciencia e Innovación (MICIN). España
|Citation||Gage, K.R., Chen, X., Van Zeeland, M., Heidbrink, W.W., Hanson, J., Lyons, B.,...,García Muñoz, M. (2023). Impact of β n and Spectrum of n = 1 Applied Fields on Fast ion Losses in DIII-D. Nuclear Fusion, 63 (3), 036002. https://doi.org/10.1088/1741-4326/acb21f.|