First measurements of velocity-space resolved intra-ELM fast-ion losses on the TCV tokamak

Edge Localised Modes (ELMs) induced fast-ion losses have been characterised in the energy, E, and pitch, λ = v∥/v, space using a unique Fast Ion Loss Detector (FILD) on the tokamak à configuration variable. The FILD is equipped with a 128 Avalanche Photo Diodes (APDs) camera measuring scintillator e...

Full description

Authors: Poley-Sanjuán, J.; Jansen van Vuuren, A.; Galdón Quiroga, Joaquín; Mazzi, S.; Podestà, M.; Dreval, M.B.; Duval, B. P.; Fasoli, A.; Karpushov, A. N.; Labit, B.; Kumar, U.; EUROfusion Tokamak Exploitation Team; TCV Team
Format: Article
Status:Published version
Publication date:2025
Country:España
Institution:Universidad de Sevilla (US)
Repository:idUS. Depósito de Investigación de la Universidad de Sevilla
OAI Identifier:oai:dnet:idus________::26ca94332fbed6d5777835182e8846ca
Online Access:https://hdl.handle.net/11441/186015
https://doi.org/10.1088/1741-4326/adf95b
Access Level:Open access
Keyword:Fast particles
FILD
ELMs
Microsecond velocity-space
Acceleration
Summary:Edge Localised Modes (ELMs) induced fast-ion losses have been characterised in the energy, E, and pitch, λ = v∥/v, space using a unique Fast Ion Loss Detector (FILD) on the tokamak à configuration variable. The FILD is equipped with a 128 Avalanche Photo Diodes (APDs) camera measuring scintillator emission with a 1 MHz bandwidth. The well-defined view lines of the APDs allow for obtaining velocity space information from the emission pattern with unprecedented temporal resolution. Making use of the enhanced FILD capabilities, ELM-induced fast-ion losses were investigated in the ITER Baseline Scenario, mimicking its shape and normalised plasma parameters. Significant fast-ion losses were observed, notably before and during the ELM crashes induced by the presence of a 2/1 MHD instability localised at the plasma’s normalised radius, ρ ∼ 0.7. The fast-ion interaction with the plasma instability is concluded to be unconnected to the presence of the ELMs. During the ELM crashes, there is an observed spread in both the fast-ion pitch and energy that reaches higher values (∼70 keV) than expected from the pre-ELM fast-ion population, generated by Neutral Beam Injection at ∼27 keV. This implies a fast-ion acceleration during the ELM’s crash. Full orbit neoclassical simulations are used to calculate the neoclassical fast-ion velocity space lost to the FILD and to quantify the neoclassical fast-ion losses.

Similar Items