Berlin 2014 – scientific programme
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P: Fachverband Plasmaphysik
P 12: Poster Session - Magnetic Confinement
P 12.1: Poster
Tuesday, March 18, 2014, 16:30–18:30, SPA Foyer
Revision of the Spectroscopic Determination of Beam Parameters of the Neutral Beam Injection Systems on ASDEX Upgrade — •Felician Mink, Christian Hopf, and Ursel Fantz — Max-Planck-Institut für Plasmaphysik, EURATOM Association, Boltzmannstr. 2, 85748 Garching, Germany
Neutral beam injection is a frequently used powerful heating system on contemporary magnetic confinement fusion experiments such as ASDEX Upgrade. The injected beam is also used for plasma diagnostics based on charge exchange recombination spectroscopy. Increasing precision of these spectroscopic diagnostics as well as modern plasma transport codes require increasingly precise knowledge of the beam’s geometry and composition as input.
These parameters are typically obtained through Dα beam emission Doppler spectroscopy.
Traditionally, a single number for the beam’s divergence is obtained from these spectra using a simplified two-dimensional model and Gaussian fits. We replace this model with a fully 3-dimensional simulation of the Doppler-broadened spectra. The species distribution, i.e. the contribution of D+, D2+ and D3+ to the primary ion beam, is derived from the ratios of the corresponding peak intensities. We critically review the validity of the usually applied Corona model and investigate experimentally in what parameter range collisional de-excitation has to be taken into account.