量研学術機関リポジトリ「QST-Repository」は、国立研究開発法人 量子科学技術研究開発機構に所属する職員等が生み出した学術成果（学会誌発表論文、学会発表、研究開発報告書、特許等）を集積しインターネット上で広く公開するサービスです。 Welcome to QST-Repository where we accumulates and discloses the academic research results(Journal Publications, Conference presentation, Research and Development Report, Patent, etc.) of the members of National Institutes for Quantum and Radiological Science and Technology.
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Existing methods for diagnostics and control are still insufficient to deal with the various kinds of instabilities and collective dynamics that occur in magnetically confined fusion plasmas, which may impact the missions of the ITER and DEMO projects. Using small-scale laser experiments on J-KAREN-P, numerical simulations on the JFRS-1 supercomputer and theoretical analyses, we are investigating whether short pulses (ps-fs) of a high power laser (TW-PW) may be used to address some of these issues. The object of interest is the electron-free positively charged plasma wake channel that is carved out by a laser pulse with relativistic intensity. Using the relativistic PIC codes EPOCH and REMP, we simulate the long-time evolution of such wake channels in the presence of a strong magnetic field (~2T) as is typical for tokamaks. We demonstrate that there exists a parameter window where the after-glow dynamics of the magnetized wake channels are effectively independent of the laser wavelength. This justifies scaled simulations with artificially increased wavelengths, which
reduces the computational expenses to the point where long-time 3D simulations become feasible. We compare the results of recent 2D and 3D simulations and examine the effects of the plasma density and magnetic field strength via parameter scans. In particular, we will report our observations regarding particle acceleration, charge separation and the generation of magnetic vortices. First insights concerning the role of thermal motion will be discussed along with possible implications for tokamak plasma control and diagnostics.
会議概要（会議名, 開催地, 会期, 主催者等）
5th UNIST - Kyoto University Workshop on "Physics validation and control of MHD instabilities and turbulent transport in fusion plasmas"
Effect of a relativistically intense laser pulse in a tokamak plasma: Results of scaled simulations and experiments in cold gas limit
