Statistical analysis of non-Maxwellian electron distribution functions measured with angularly resolved Thomson scattering

• Published in: Physics of plasmas 2021-08, Vol.28 (8)
• Main Authors: Milder, A. L., Katz, J., Boni, R., Palastro, J. P., Sherlock, M., Rozmus, W., Froula, D. H.
• Format: Article
• Language: English
• Subjects: 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; Bremsstrahlung; Distribution functions; Electron density; Electron distribution; Electron velocity distribution; Gas jet; Laser plasma interactions; Maxwell-Boltzmann distribution; Maxwellian distribution; Monte Carlo methods; Plasma physics; Plasma properties and parameters; Plasma waves; Probability theory; Statistical analysis; Thomson scattering; Uncertainty
• ISSN: 1070-664X; 1089-7674
• DOI: 10.1063/5.0041504

Angularly resolved Thomson scattering is a novel extension of Thomson scattering, enabling the measurement of the electron velocity distribution function over many orders of magnitude. Here, details of the theoretical basis of the technique and the instrument designed for this measurement are described. Angularly resolved Thomson-scattering data from several experiments are shown with descriptions of the corresponding distribution functions. A reduced model describing the distribution function is given and used to perform a Monte Carlo analysis of the uncertainty in the measurements. The electron density and temperature were determined to a precision of 12% and 21%, respectively, on average, while all other parameters defining the distribution function were generally determined to better than 20%. It was found that these uncertainties were primarily due to limited signal to noise and instrumental effects. Measurements with this level of precision were sufficient to distinguish between Maxwellian and non-Maxwellian distribution functions.