Collective optical Thomson scattering in pulsed-power driven high energy density physics experiments (invited)

• DOI: 10.1063/5.0041118
• Publication Date: 2021-03-23T11:51:18Z
• Authors: L. G. Suttle; J. D. Hare; J. W. D. Halliday; S. Merlini; D. R. Russell; E. R. Tubman; V. Valenzuela-Vil...; W. Rozmus; C. Bruulsema; S. V. Lebedev
• Keywords: Thomson scattering; Electron temperature

Optical collective Thomson scattering (TS) is used to diagnose magnetized high energy density physics experiments at the Magpie pulsed-power generator Imperial College London. The system uses an amplified pulse from second harmonic of a Nd:YAG laser (3 J, 8 ns, 532 nm) probe wide diversity high-temperature plasma objects, with densities in range 1017–1019 cm−3 and temperatures between 10 eV few keV. scattered light collected 100 μm-scale volumes within plasmas, which are imaged onto optical fiber arrays. Multiple collection systems observe these different directions, providing simultaneous probing K-vectors (and associated α-parameters, typically 0.5–3), allowing independent measurements separate velocity components bulk flow. arrays coupled imaging spectrometer gated intensified charge device. configured view ion-acoustic waves spectrum. Fits spectra theoretical spectral function S(K, ω) yield local velocities. Fitting constrained by electron interferometry corresponding for vectors. This TS diagnostic has been successfully implemented on experiments, revealing temperature flow transitions across shocks, inside rotating jets imploding wire arrays, as well direct drift velocities magnetic reconnection current sheet.