Diagnostics of microwave discharge low-pressure argon plasma by multi-optical emission line analysis based on collisional-radiative model
| Autor: | Yamashita, Yuya, Yamazaki, Fuminori, Nezu, Atsushi, AKATSUKA, HIROSHI |
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| Jazyk: | japonština |
| Rok vydání: | 2018 |
| Zdroj: | 第65回応用物理学会春季学術講演会講演予稿集. :07-023 |
| Popis: | 衝突輻射モデルに基づいた原子過程モデルを用いた，多数の発光線強度を入力とした，低気圧アルゴンプラズマに対する筆者らが提案する電子温度および電子密度診断法を検証した．マイクロ波放電プラズマを対象として，プローブ計測との対照実験を行った．マイクロ波電力および測定位置との依存性を測定した結果，特に電子密度についてはプローブ計測の傾向と一致することが確認でき，提案手法の妥当性が明らかとなった． Line-pair method cannot be applied to wide-range electron temperature Te and density Ne diagnostics of plasmas in the state of non-equilibrium. Although the method using multi-emission lines is suitable, little has been reported for the low-pressure plasma measurement. We proposed the optical emission spectroscopic (OES) diagnostic method for the low-pressure argon plasma. In this presentation, the applicability for the microwave discharge argon plasma is reported. Based on the Ar collisional-radiative (CR) model, the dominant elementary possesses were extracted for the excitation kinetics for several excited states. And, the excitation-kinetic model for the OES diagnostics was established. As a result, the diagnostic model was obtained. In the model, input parameter is 15 optical emission lines (wavelength range: 340.7 – 912.5nm). Possible measurement range is 1.0 ≤ Te [eV] ≤ 3.8, and 1.0 × 109 ≤ Ne [cm-3] ≤ 5.0 × 1012. In order to examine the validity of the proposed method, microwave discharge argon plasma was diagnosed with (A) probe measurement: (A-1) under the assumption that the electron density distribution function (EEDF) is Maxwellian, (A-2) together with the measurement of the EEDF by the Druyvesteyn’s method, and equivalent Te measurement; and (B) OES measurement by the present proposed method at points (from the center of the waveguide) = 10, 14, and 18 cm, with the microwave power = 100, 300, and 500 W. Concerning Ne diagnosis, the trend of Ne determined with the scheme (B) was in good agreement with the scheme (A-1). Meanwhile, as for Te diagnosis, it was difficult to evaluate, because the result of the scheme (B) reached the limit value of root-finding range in the numerical procedure. However, at least, the result of (A-1) is considered to be reasonable. And by using input with arbitrary shaped EEDF is measured by the OES measurement, and the resultant improvement of the diagnostic result can be expected. |
| Databáze: | OpenAIRE |
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