Understanding and control of plasma detachment caused by composite gas seeding

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K03790
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 14020:Nuclear fusion-related
• Research Institution: University of Tsukuba
• Principal Investigator: Ezumi Naomichi 筑波大学, 数理物質系, 准教授 (20321432)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 非接触プラズマ / ダイバータ / プラズマ-ガス相互作用 / 原子分子過程 / 分子活性化再結合 / 窒素 / 水素 / ターゲット形状

Outline of Final Research Achievements

Remarkable progress has been made on the understanding the role of N2 and H2 seeding on plasma detachment in divertor simulation experiments using the end-loss region of the tandem mirror device GAMMA 10/PDX. These issues have been experimentally investigated for different gas species, seeding rate and target angles. We have newly observed Nitrgoen Molecular Assisted/Activated Recombination (N-MAR) processes during combination seeding of N2 and H2 which led to a clear decrease of ion flux to the divertor target. Simultaneously, spectrum emission from the NH radical has been observed. The results indicate the importance of molecular gas behavior for not only heat load control in fusion device, but also application for such as nitride processing, ammonia production and so on. Furthermore, V-shaped target experiment in different target angles shows an area of Hydrogen-MAR move to upstream in the case of small angle slot.

Free Research Field

プラズマ理工学、核融合学

Academic Significance and Societal Importance of the Research Achievements

本研究の主な成果であるプラズマ中での窒素-水素の反応過程の理解は、核融合炉実現において重要な課題のひとつである定常的な高熱流束プラズマに晒されるダイバータ板への熱負荷低減に不可欠な非接触プラズマ制御の高度化に寄与するものである。また、その反応過程の理解は窒素、水素を利用する産業応用分野においても重要な知見となると考えられる。