Heat-flow change induced by active radiation loss in open magnetic flux of steady-state spherical tokamak

2016 Fiscal Year Final Research Report

• Project/Area Number: 15K17800
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Plasma science
• Research Institution: Kyushu University
• Principal Investigator: Onchi Takumi 九州大学, 応用力学研究所, 学術研究員 (00727216)
• Project Period (FY): 2015-04-01 – 2017-03-31
• Keywords: プラズマ熱流束 / 放射損失 / 球状トカマク / スクレイプオフ層

Outline of Final Research Achievements

Damage of plasma facing component (PFC) is a serious issue for future nuclear fusion reactor, where plasma is confined magnetically. Active radiation-loss is one of the methods to reduce heat flux on PFCs. This experiment is a bench test to investigate effect of active radiation-loss. In the spherical tokamak QUEST, electron temperature, density, heat flux, and velocity of plasma flow are measured in the far scrape-off layer (SOL) and the end-plate. Substantial flow of particles and heat from the SOL to the end-plate is observed after strong gas puffing with high radiation-loss. Increase of electron density and decrease of electron temperature occur before a disruption with high H alpha line-emission in a 2 hours-long pulse tokamak operation. In addition, a system for super-sonic molecular beam injection to induce local radiation-loss has been prepared.

Free Research Field

プラズマ理工学