Fast-ion redistribution and loss due to edge perturbations in the ASDEX Upgrade, DIII-D and KSTAR tokamaks
|Author/s||García Muñoz, Manuel
Boom, J. E.
Classen, I. G. J.
Rodríguez Ramos, Mauricio
|Department||Universidad de Sevilla. Departamento de Física Atómica, Molecular y Nuclear|
|Abstract||The impact of edge localized modes (ELMs) and externally applied resonant and non-resonant magnetic perturbations
(MPs) on fast-ion confinement/transport have been investigated in the ASDEX Upgrade (AUG), DIII-D and ...
The impact of edge localized modes (ELMs) and externally applied resonant and non-resonant magnetic perturbations (MPs) on fast-ion confinement/transport have been investigated in the ASDEX Upgrade (AUG), DIII-D and KSTAR tokamaks. Two phases with respect to the ELM cycle can be clearly distinguished in ELM-induced fast-ion losses. Inter-ELM losses are characterized by a coherent modulation of the plasma density around the separatrix while intra-ELM losses appear as well-defined bursts. In high collisionality plasmas with mitigated ELMs, externally applied MPs have little effect on kinetic profiles, including fast-ions, while a strong impact on kinetic profiles is observed in low-collisionality, low q 95 plasmas with resonant and non-resonant MPs. In low-collisionality H-mode plasmas, the large fast-ion filaments observed during ELMs are replaced by a loss of fast-ions with a broad-band frequency and an amplitude of up to an order of magnitude higher than the neutral beam injection prompt loss signal without MPs. A clear synergy in the overall fast-ion transport is observed between MPs and neoclassical tearing modes. Measured fast-ion losses are typically on banana orbits that explore the entire pedestal/scrape-off layer. The fast-ion response to externally applied MPs presented here may be of general interest for the community to better understand the MP field penetration and overall plasma response.
|Citation||García Muñoz, M., Äkäslompolo, S., Asunta, O., Boom, J.E., Chen, X., Classen, I.G.J.,...,Wolfrum, E. (2013). Fast-ion redistribution and loss due to edge perturbations in the ASDEX Upgrade, DIII-D and KSTAR tokamaks. Nuclear Fusion, 53, 123008 (9pp). https://doi.org/10.1088/0029-5515/53/12/123008.|