Combination of fast-ion diagnostics in velocity-space tomographies

M. Salewski, B. Geiger, S.K. Nielsen, H. Bindslev, M. García-Muñoz, W.W. Heidbrink, S.B. Korsholm, F. Leipold, J. Madsen, F. Meo, P.K. Michelsen, D. Moseev, M. Stejner, G. Tardini

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

Fast-ion D α (FIDA) and collective Thomson scattering (CTS) diagnostics provide indirect measurements of fast-ion velocity distribution functions in magnetically confined plasmas. Here we present the first prescription for velocity-space tomographic inversion of CTS and FIDA measurements that can use CTS and FIDA measurements together and that takes uncertainties in such measurements into account. Our prescription is general and could be applied to other diagnostics. We demonstrate tomographic reconstructions of an ASDEX Upgrade beam ion velocity distribution function. First, we compute synthetic measurements from two CTS views and two FIDA views using a TRANSP/NUBEAM simulation, and then we compute joint tomographic inversions in velocity-space from these. The overall shape of the 2D velocity distribution function and the location of the maxima at full and half beam injection energy are well reproduced in velocity-space tomographic inversions, if the noise level in the measurements is below 10%. Our results suggest that 2D fast-ion velocity distribution functions can be directly inferred from fast-ion measurements and their uncertainties, even if the measurements are taken with different diagnostic methods.

Original languageEnglish
Article number063019
JournalNuclear Fusion
Volume53
Issue number6
Number of pages10
ISSN0029-5515
DOIs
Publication statusPublished - 1. Jun 2013
Externally publishedYes

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