Improving pulsed laser induced fluorescence distribution function analysis through matched filter signal processing.

Autor: Gilbert TJ, Steinberger TE, Scime EE
Jazyk: angličtina
Zdroj: The Review of scientific instruments [Rev Sci Instrum] 2024 Aug 01; Vol. 95 (8).
DOI: 10.1063/5.0215510
Abstrakt: Laser induced fluorescence is used to measure argon ion heating during magnetic reconnection in the PHase Space MApping experiment (PHASMA). Sufficient signal-to-noise ratio (SNR) of the processed signal with pulsed laser injection is a delicate balance between saturation of the absorption line and injecting enough laser power to overcome the spontaneous emission of the plasma at the fluorescence wavelength. Averaging over many laser pulses and integrating over the fluorescence lifetime improves the SNR of the processed signal (processed SNR) when the SNR of the laser pulse time series is small (pulse SNR), but for laser powers small enough to avoid saturation, averaging over hundreds of pulses is needed to obtain an appreciable processed SNR over the entire Doppler-broadened absorption line. Here, we describe a matched filter processing method that significantly improves the SNR of the final measurement with fewer shots averaged. Investigation of simulated measurements validated by experimental results suggests that the matched filter method provides up to a 20% improvement in the processed SNR, resulting in less uncertainty in distribution function fits.
(© 2024 Author(s). Published under an exclusive license by AIP Publishing.)
Databáze: MEDLINE