2022 Fiscal Year Final Research Report

Investigation of the relationship between the conditions of High-Z ionised plasma production and radiation spectra using collective Thomson scattering.

Research Project

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Project/Area Number	20H01880
Research Category	Grant-in-Aid for Scientific Research (B)
Allocation Type	Single-year Grants
Section	一般
Review Section	Basic Section 14010:Fundamental plasma-related
Research Institution	Hokkaido University
Principal Investigator	Tomita Kentaro 北海道大学, 工学研究院, 准教授 (70452729)
Co-Investigator(Kenkyū-buntansha)	砂原淳大阪大学, レーザー科学研究所, 招へい准教授 (00370213) 西原功修大阪大学, レーザー科学研究所, 名誉教授 (40107131)
Project Period (FY)	2020-04-01 – 2023-03-31
Keywords	トムソン散乱 / レーザー生成プラズマ / 電子温度 / 電子密度 / 軟X線 / EUV
Outline of Final Research Achievements	In-situ measurements of the two-dimensional spatial profiles and time evolution of the electron density, electron temperature, averaged ionic charge, and velocity field of laser-produced plasmas (LPPs) were successfully performed using the collective Thomson scattering technique. These measurements were carried out mainly on a solid carbon target, which is relatively easy to measure. Based on these results, Thomson scattering measurements were performed to a Gd target, which is expected to be a light source in the 6 nm wavelength band, and where the high laser power density of the Gd plasma is expected to realise high temperature conditions. The energy loss due to pressure gradients (expansion loss) is expected to increase. From an engineering point of view, it is important to clarify the relationship between the input laser power and the electron temperature. We cralified the relations. Translated with www.DeepL.com/Translator (free version)
Free Research Field	プラズマ科学
Academic Significance and Societal Importance of the Research Achievements	軟X線およびEUV領域における半導体露光光源として、レーザー生成プラズマ光源の開発は重要である。そこでは不透明なプラズマが、非一様・非定常に存在している。光の発生や輸送過程はプラズマの密度・温度で決定されるため、光源プラズマ内の密度・温度計測は現象把握に必須項目でありながら、計測が技術的に困難であり達成されてこなかった。本研究ではそれを打破できる新たな協同的トムソン散乱システムを基軸として、レーザープラズマの密度・温度だけでなく、流体運動で重要な速度場をも実計測可能とした点で学術的な意義は大きい。さらに実用的な軟X線光源について、投入レーザー強度と電子温度の関係を明らかにした点も意義がある。