Time-Resolved Thomson Scattering on Laboratory Plasma Jets

Banasek, Jacob; Byvank, Tom; Rocco, Sophia; Potter, Walter D.; Kusse, B. R.; Hammer, D. A.

doi:10.1109/tps.2018.2850278

Cited by 12 publications

(1 citation statement)

References 14 publications

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“…The collection of sub-nanosecond (sub-ns) time-resolved TS signals for a total time of 7 ns was achieved by establishing two observation angles (90°and 30°) [9]. A similar ns-level TS technique has been developed by splitting the incident laser beam into two paths [10]. One of the paths was delayed with respect to the other by 3-14 ns.…”

Section: Introductionmentioning

confidence: 99%

Pulse-burst laser-based 10 kHz Thomson scattering measurements

Smith

Biewer

et al. 2019

Plasma Sci. Technol.

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Thomson scattering (TS), as a popular and reliable diagnostic technique, has successfully measured electron temperatures and electron number densities of plasmas for many years. However, conventional TS techniques using Nd:YAG lasers operate only at tens of hertz. Here, we present the development of a high-repetition-rate TS instrument based on a high-speed, pulse-burst laser system to greatly increase the temporal resolution of measurements. Successful instrument prototype testing was carried out by collecting TS light from laboratory helium and argon plasmas at 10 kHz. Calibration of the instrument detection sensitivity using nitrogen/ oxygen rotational Raman scattering signal is also presented. Quantitative electron number densities and electron temperatures of the plasma were acquired at 10 kHz, for stable plasma discharges as, respectively, ∼0.9 eV and ∼5.37×10 21 m −3 for the argon plasma, and ∼1 eV and ∼6.5×10 21 m −3 for the helium plasma.

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Section: Introductionmentioning

confidence: 99%

Pulse-burst laser-based 10 kHz Thomson scattering measurements

Smith

Biewer

et al. 2019

Plasma Sci. Technol.

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Bayesian inference of plasma parameters from collective Thomson scattering technique on a gas-puff near stagnation

Escalona,

Valenzuela,

Avaria

et al. 2023

Sci Rep

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The Collective Thomson scattering technique has been implemented to study the stagnation of a single liner gas-puff. The plasma parameters are determined by theoretically modelling the scattering form factor in combination with Bayesian inference to provide the set of the most probable parameters that describe the experimental data. Analysis of the data reveal that incoming flows are able to interpenetrate partially. Estimation of the mean free path shows a gradual transition from a weakly collisional to a collisional regime as the plasma gets to the axis. Furthermore, we find that the ion energy at $$\mathrm{r}=2.5\,\mathrm{mm}$$ r = 2.5 mm is $${13.6}_{-0.9}^{+1.0}\,\mathrm{keV}$$ 13.6 - 0.9 + 1.0 keV and is mostly kinetic in nature and represents $${98}_{-9}^{+10} \%$$ 98 - 9 + 10 % of the total energy. This kinetic energy is far greater than the value on axis of $${3.7}_{-0.5}^{+0.4}\,\mathrm{keV}$$ 3.7 - 0.5 + 0.4 keV which is $${84}_{-14}^{+15} \%$$ 84 - 14 + 15 % of the total energy. Energy transfer to the electrons and radiation losses are found to be negligible by this time. A possible explanation for this energy imbalance is the presence of an azimuthal magnetic field larger than $$\sim 4.7\,\mathrm{T}$$ ∼ 4.7 T that deflect the ions vertically. The uncertainties quoted represent 68% credible intervals.

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Multi-angle multi-pulse time-resolved Thomson scattering on laboratory plasma jets

Banasek

Rocco

Potter

et al. 2018

Review of Scientific Instruments

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A single channel sub-nanosecond time-resolved Thomson scattering system used for pulsed power-driven high energy density plasma measurements has been upgraded to give electron temperatures at two different times and from two different angles simultaneously. This system was used to study plasma jets created from a 15 μm thick radial Al foil load on a 1 MA pulsed power machine. Two laser pulses were generated by splitting the initial 2.3 ns duration, 10 J, 526.5 nm laser beam into two pulses, each with 2.5 J, and delaying one relative to the other by between 3 and 14 ns. Time resolution within each pulse was obtained using a streak camera to record the scattered spectra from the two beams from two scattering angles. Analysis of the scattering profile showed that the electron temperature of the Al jet increased from 20 eV up to as much as 45 eV within about 2 ns by inverse bremsstrahlung for both laser pulses. The Thomson scattering results from jets formed with opposite current polarities showed different laser heating of the electrons, as well as possibly different ion temperatures. The two-angle scattering determined that the electron density of the plasma jet was at least 2 × 1018 cm−3.

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Time-Resolved Thomson Scattering on Laboratory Plasma Jets

Cited by 12 publications

References 14 publications

Pulse-burst laser-based 10 kHz Thomson scattering measurements

Pulse-burst laser-based 10 kHz Thomson scattering measurements

Bayesian inference of plasma parameters from collective Thomson scattering technique on a gas-puff near stagnation

Multi-angle multi-pulse time-resolved Thomson scattering on laboratory plasma jets

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