Abstrakt
This article describes a fast and automatic reconstruction of the edge plasma electron density from the radiation of energetic Li atoms of the diagnostic beam on the COMPASS tokamak. Radiation is detected by using a CCD camera and by using an avalanche photo-diode system with a temporal resolution of 20 ms and 2 mu s, respectively.
Both systems are equipped with a 670.8 nm optical filter which corresponds to the lithium 1s(2)2s(1)-1s(2)2p(1) transition. A theoretical model and a data processing procedure of a raw signal to obtain the density profile are described.
The reconstruction algorithm provides the absolutely calibrated electron density profiles together with the measurement error estimated from relatively calibrated light profiles; the implementation is performed in Python. Time demanding operations of the code were optimized to provide reconstruction of a single profile within less than 10 ms which makes the code applicable for processing of a large amount of data.
Thanks to this calculation speed, it is possible to reconstruct electron density profiles between two consecutive shots on the COMPASS tokamak with 2 mu s time resolution. Published by AIP Publishing.