Novel inferences of ionisation & recombination for particle/power balance during detached discharges using deuterium Balmer line spectroscopy

• Published in: arXiv.org
• Main Authors: Verhaegh, K, Lipschultz, B, Duval, B P, Fil, A, Wensing, M, Bowman, C, Gahle, D S
• Format: Paper Journal Article
• Language: English
• Published: Ithaca Cornell University Library, arXiv.org 27.11.2019
• Subjects: Computer simulation; Deuterium; Diagnostic systems; Emission analysis; Energy costs; Erosion; Excitation; Heat sinks; Ion flux; Ion recombination; Ion sources; Ionization; Physics - Data Analysis, Statistics and Probability; Physics - Plasma Physics; Probability density functions; Statistical analysis; Tokamak devices
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.1903.08157

The physics of divertor detachment is determined by divertor power, particle and momentum balance. This work provides a novel analysis technique of the Balmer line series to obtain a full particle/power balance measurement of the divertor. This supplies new information to understand what controls the divertor target ion flux during detachment. Atomic deuterium excitation emission is separated from recombination quantitatively using Balmer series line ratios. This enables analysing those two components individually, providing ionisation/recombination source/sinks and hydrogenic power loss measurements. Probabilistic Monte Carlo techniques were employed to obtain full error propagation - eventually resulting in probability density functions for each output variable. Both local and overall particle and power balance in the divertor are then obtained. These techniques and their assumptions have been verified by comparing the analysed synthetic diagnostic 'measurements' obtained from SOLPS simulation results for the same discharge. Power/particle balance measurements have been obtained during attached and detached conditions on the TCV tokamak.