Fast-ion velocity-space tomography using slowing-down regularization in EAST plasmas with co- and counter-current neutral beam injection. (5th October 2020)

• Record Type: Journal Article
• Authors: Madsen, B; Huang, J; Salewski, M; Järleblad, H; Hansen, P C; Stagner, L; Su, J; Chang, J F; Fu, J; Wang, J F; Liang, L Z; Zhong, G Q; Li, Y Y; Lyu, B; Liu, H Q; Zang, Q; Luo, Z P; Nocente, M; Moseev, D; Fan, T S; Zhang, Y M; Yang, D; Sun, J Q; Liao, L Y
• Other Names: collab.
• Is Part Of: Plasma physics and controlled fusion. Volume 62:Number 11(2020)
• Publication Date: 2020-10-05
• Subjects: velocity-space tomography -- fast-ion D-alpha spectroscopy -- fast ions -- slowing-down regularization -- EAST tokamak; Plasma (Ionized gases) -- Periodicals; Controlled fusion -- Periodicals; 530.44
• DOI: 10.1088/1361-6587/abb79b
• Languages: English
• ISSNs: 0741-3335

Abstract

Abstract: We demonstrate 2D reconstructions of the fast-ion velocity distribution from two-view fast-ion D-alpha (FIDA) measurements at the EAST tokamak. By expressing the distribution in a basis relying on the fast-ion slowing-down process in fusion plasmas, the smoothness and velocity-space resolution of reconstructions are improved. We reconstruct distributions of fast ions born from simultaneous co- and counter-current neutral beam injection and detect the expected distinct change in fast-ion birth pitch when comparing discharges utilizing different neutral beam injectors. For purely co-current injection, we find a good agreement between TRANSP-predicted and reconstructed fast-ion densities, pressures and current densities for energies above 20 keV. We furthermore illustrate the improvement of the reconstructed high-energy range (> 40 keV) of the distribution by combining FIDA with neutron emission spectroscopy measurements with the compact single-plate EJ301 scintillator.