Main Parametric Dependencies of the Fast-Ion Edge Resonant Transport Layer Induced by 3D Perturbative Fields in the ASDEX Upgrade Tokamak

Autor: Sanchís Sánchez, Lucía, García-Muñoz, M., Snicker, A., Galdón Quiroga, Joaquín, Ryan, D. A., Nocente, M., Rivero-Rodriguez, J.F., Chen, L., Zonca, F., Suttrop, W., Viezzer, Eleonora, ASDEX Upgrade Team, EUROfusion MST1 Team
Přispěvatelé: Sanchis-Sanchez, L. [0000-0001-8211-3356], García-Muñoz, M. [0000-0002-3241-502X], Snicker, A. [0000-0001-9604-9666], Galdon-Quiroga, J. [0000-0002-7415-1894], Viezzer, Eleonora [0000-0001-6419-6848], Sanchis-Sanchez, L., García-Muñoz, M., Snicker, A., Galdon-Quiroga, J., Viezzer, Eleonora
Rok vydání: 2018
Předmět:
Zdroj: Digital.CSIC. Repositorio Institucional del CSIC
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Popis: Trabajo presentado en 23rd Joint EU-US Transport Task Force Meeting, celebrado en Sevilla (España), del 11 al 14 de septiembre de 2018
The use of non-axisymmetric fields has been widely extended for mitigating and even suppressing a broad spectrum of MHD fluctuations [1]. 3D symmetry-breaking fields can, however, cause a degradation of the particle confinement. Fast-ions are especially sensitive to 3D perturbative fields due to their relatively long mean free path and slowing down time [2]. Measurements from dedicated experiments in the ASDEX Upgrade tokamak have shown the existence of an Edge Resonant Transport Layer (ERTL), which causes energetic particle transport observed in the presence of symmetry-breaking fields. Using Monte-Carlo orbit following code ASCOT and the plasma response generated by MARS-F, simulations were carried out reproducing a strong correlation of fast-ion loss intensity with the perturbation poloidal spectra. This work presents an analysis of the fast-ion resonant transport in terms of the variation in the particle toroidal canonical momentum (δPφ) in the presence of 3D perturbative fields generated by different coil configurations. A scan in poloidal spectra, q95 and collisionality was carried out to assess the impact of each different contribution. In figure 1, the fast-ion is presented as a function of the particle initial energy and radius (a) and particle initial radius and toroidal angle (b) for a fixed coil configuration, showing how the relative position of the particle with respect to the perturbation can affect the transport. The ERTL properties depend strongly on the fast-ion orbit topology, the perturbation spectra, the magnetic background helicity (q95) and the plasma collisionality. This study may help to optimize the fast-ion confinement in the presence of externally applied 3D fields in present and future devices.
Databáze: OpenAIRE