Dynamics of lithium plasma in laser-induced breakdown spectroscopy

Marenkov, E.D.; Tsygvintsev, I.P.; Kim, D.A.; Grushin, A.S.; Efimov, N.E.; Sinelnikov, D.N.; Gasparyan, Yu.M.

doi:10.1016/j.sab.2023.106822

Cited by 2 publications

(1 citation statement)

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“…The laser techniques for the analysis of the tokamak first wall are based on using the laser radiation to remotely heat the surface of the tokamak tiles and register either the radiation signal from the gas cloud/plasma plume formed near the target surface or the particle flux from the tile surface. A broad range of methods such as the Laser-Induced Breakdown Spectroscopy (LIBS) [7,8,11,[13][14][15][16][17][18][19][20][21][22], Laser-Induced Ablation Light [6,9,[23][24][25][26] /Mass [27][28][29][30][31] Spectroscopy (LIAS/LIA-QMS), and also the Laser-Induced-Desorption Light [6,32,33] and Mass [10,26,31,32,[34][35][36][37][38][39][40] Spectrometry (LIDS/LID-QMS) were proposed for analysis of tritium content in the tokamak plasma facing materials.…”

Section: Introductionmentioning

confidence: 99%

Dimensional effects in analysis of laser-induced-desorption diagnostics data

Stepanenko,

Gasparyan

2024

Phys. Scr.

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The accurate assessment of the local tritium concentration in the tokamak first wall by means of the laser-induced desorption (LID) diagnostics is sought as one the key solutions to monitoring the local radioactive tritium content in the first wall of the fusion reactor ITER. Numerical models of gas desorption from solids used for LID simulation are usually closed with the one-dimensional transport models. In this study, the temperature and particle dynamics in the target irradiated by a short laser pulse during LID are analyzed by means of the two-dimensional model to assess the validity of using one-dimensional approximation for recovering the diagnostics signal. The quantitative estimates for the parameters governing the heat and particle transfer are presented. The analytical expressions for the sample spatiotemporal temperature profiles driven by the target irradiation with a Gaussian laser beam with the trapezoid temporal shape are derived. The obtained relations are used to simulate tritium desorption from a tungsten sample driven by pulsed heating. It is shown that depending of the ratio between the laser spot radius and the heat diffusion length, the one-dimensional approach can noticeably overestimate the sample temperature in the limit of small laser spot radius (estimated for tungsten as ∼ 0.5 − 1.0 mm), resulting in more than 100% larger amounts of tritium desorbed from the target, compared to the two-dimensional approximation. In the limit of large laser spot radius (≥ 1.5 mm), both approaches yield comparable amounts of tritium desorbed from the sample.

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