Schmidt, B. S.Salewski, M.Moseev, D.Baquero-Ruiz, M.Hansen, P. C.Eriksson, J.Ford, O.Gorini, G.Jarleblad, H. O.Kazakov, YeKulla, D.Lazerson, S.Mencke, J. E.Mykytchuk, D.Nocente, M.Poloskei, P.Rud, M.Snicker, A.Stagner, L.Aekaeslompolo, S.2023-06-192023-06-192023-06-192023-07-0110.1088/1741-4326/acd6a6https://infoscience.epfl.ch/handle/20.500.14299/198486WOS:000997174200001We compute reconstructions of 4D and 5D fast-ion phase-space distribution functions in fusion plasmas from synthetic projections of these functions. The fast-ion phase-space distribution functions originating from neutral beam injection (NBI) at TCV and Wendelstein 7-X (W7-X) at full, half, and one-third injection energies can be distinguished and particle densities of each component inferred based on 20 synthetic spectra of projected velocities at TCV and 680 at W7-X. Further, we demonstrate that an expansion into a basis of slowing-down distribution functions is equivalent to regularization using slowing-down physics as prior information. Using this technique in a Tikhonov formulation, we infer the particle density fractions for each NBI energy for each NBI beam from synthetic measurements, resulting in six unknowns at TCV and 24 unknowns at W7-X. Additionally, we show that installing 40 LOS in each of 17 ports at W7-X, providing full beam coverage and almost full angle coverage, produces the highest quality reconstructions.Physics, Fluids & PlasmasPhysicsfast ionstomographyslowing-downnbitokamakstellaratortext::journal::journal article::research article