2025.06.20

メタ階層ダイナミクスユニットセミナーを開催します。皆様のご参加お待ちしております。

【日時】 2025年6月25日（水）13:30-15:00

【場所】 核融合科学研究所 研究I期棟8階801会議室＋Zoom

【講演1】

Models for Stark broadening in astrophysical and laboratory plasmas

Ibtissem Hannachi ／ 客員准教授（バトゥナ第１大学）

The Stark broadening of hydrogen spectral lines is a key tool for diagnosing both astrophysical and laboratory plasmas. Early models explained this broadening by considering how collisions with charged particles shorten the lifetime of the radiating atom. The Lorentz model successfully described line shapes broadened by electrons and was later extended to include the effect of static ions, forming the standard theory of Stark broadening. While this standard model agrees well with observations in dense arc plasmas, it becomes inaccurate for the lower-density plasmas found in many astrophysical and fusion environments.
To address these limitations, we present models that incorporate ion dynamics, such as the frequency fluctuation model used in the PPP code, and a plasma simulation coupled with numerical integration of the Schrödinger equation for the emitter. These simulation approaches also enable the study of the effects of simultaneous periodic electric fields. We discuss potential spectroscopic diagnostics enabled by these models, with a focus on applications in magnetic fusion devices.

【講演2】

近赤外分光を用いたダイバータプラズマ診断 / Divertor plasma diagnostics using near-infrared spectroscopy

四竈泰一 ／ 客員准教授（京都大学）

近赤外域における輝線プロファイルの精密分光は、輝線に含まれる電磁場や粒子温度・流速などの情報を分離して取得するための有効な方法である。我々は本方法を活用し、核融合プラズマのダイバータ診断、プラズマ波動に起因する交流電場の計測、電子速度分布の異方性で生じる輝線偏光の高精度計測などに取り組んでいる。本セミナーでは、ダイバータ診断における工学的要求を背景として、近赤外分光によって観測可能な物理量、実験上の課題について概説する。

High-resolution spectroscopy of emission line profiles in the near-infrared region is an effective method for isolating and extracting physical information included in the spectral lines, such as electromagnetic fields, and particle temperatures and flow velocities. We are utilizing this method to address several research topics, including divertor diagnostics in fusion plasmas, measurement of AC electric fields induced by plasma waves, and high-precision detection of emission line polarization resulting from anisotropic electron velocity distributions. In this seminar, I will talk about an overview of the measurable physical quantities by near-infrared spectroscopy along with experimental challenges in the context of engineering requirements for divertor diagnostics.

【Zoom】

https://us06web.zoom.us/j/7963832173
Passcode: 開催当日に掲載

【問い合わせ】
メタ階層ダイナミクスユニット 後藤基志（goto.motoshi(at)nifs.ac.jp）

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