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Abstract
The sensitivity of fastion diagnostics in magnetic confinement fusion can be quantified in the form of weight functions. They can be used to relate the fastion distribution function in phase space to a measurement in a diagnostic measurement bin. Via tomographic inversion, weight functions can be used to reconstruct the fastion distribution function from diagnostic measurements. Due to the magnetic field, the fast ions must follow fixed trajectories known as orbits. This work continues to build upon orbit weight functions, which can be utilized to reconstruct the full gyroaveraged fastion distribution in tokamaks. Orbit weight functions for neutron emission spectroscopy and gammaray spectroscopy for onestep fusion reactions were developed and analyzed in this project. Gained insights include: a high sensitivity to trapped orbits whose tips are inside the lineofsight of the diagnostic, and an increased understanding of the optimal positioning and orientation of diagnostic sightlines. In addition, this project also birthed new ways of using fastion orbits to analyze diagnostics. These include: 1) The decomposition of diagnostic signals, fastion distributions and weight functions, in terms of their fastion orbittype origin. 2) Interactive analysis of which fastion orbit types pass through certain (R; z) points. 3) The mapping of poloidal and toroidal transit times for all of orbit space, which could provide further insight into the interaction between fast ions and e.g. Alfvén eigenmodes. A code framework was created to enable future use of the new tools developed in this work. This is envisioned to increase the vital understanding of the behaviour of fast ions in tokamak fusion plasmas.
Original language  English 

Publisher  Department of Physics, Technical University of Denmark 

Number of pages  202 
Publication status  Published  2022 
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 1 Finished

Orbit¿space sensitivity of fast¿ion diagnostics
Järleblad, H., Lauber, P., Snicker, A. T. O., Salewski, M. & Stagner, L. E.
01/12/2019 → 27/04/2023
Project: PhD