Linear discriminant analysis based predator-prey analysis of hot electron effects on the X-pinch plasma produced K-shell Aluminum spectra

TL;DR

This paper applies Linear Discriminant Analysis to study how hot electron beams influence the spectral features of X-pinch plasma, revealing turbulence patterns and polarization effects related to electron beam presence.

Contribution

It introduces a novel application of LDA combined with predator-prey modeling to analyze hot electron effects on plasma spectra and turbulence signatures.

Findings

Electron beams cause elliptic polarization in spectral lines.

Presence of electron beams correlates with spiral turbulence patterns.

Low temperature regions are identified at the spiral centers.

Abstract

Linear Discriminant Analysis (LDA) is applied to investigate the electron beam effects on the X-pinch produced K-shell Aluminum synthetic spectra. The radiating plasma is produced by the explosion of two 25-{\mu}m Al wires on a compact L-C (40kV, 200kA and 200ns) generator and time integrated spectra are recorded using de Broglie spectrographs. The electron temperature and density(Te = 80 eV and ne = 1x1020 cm-3), as well as the hot electron beam fraction (f = 0.2 and energy centered at 10 keV) in the Al plasma, were extracted using coefficients of principal components derived from the non-LTE K-shell Al model. LDA shows that the weak transitions of Al He {\alpha} Ly {\alpha}and He {\beta} represents Stark splitting and shifting profiles. Finally, these transitions follows the elliptic polarization of Stokes V profiles in the presence of electron beam fraction. A 3-dimensional representation of LDA shows that the presence of electron beam, reflects outward spiral turbulence. These spirals show the signature of Langmuir turbulence. These spirals are modeled with logistic growth of predator-prey model. This modeling suggests that the electron beams and ions represent the preys and predator, respectively and the center region of the spirals tends to have low temperatures of 50-100 eV.