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Quasi-Periodic Mitigation of Runaway Electron Beam via Interaction with Kinetic Instabilities in the QUEST Spherical Tokamak

Thomas K. CLOAREC¹⁾, Ryuya IKEZOE²⁾, Kazuaki HANADA²⁾, Makoto HASEGAWA²⁾, Hiroshi IDEI²⁾, Takeshi IDO²⁾, Toshiki KINOSHITA²⁾, Yoshihiko NAGASHIMA²⁾, Takumi ONCHI²⁾

1)

Université Paris-Saclay, ENS Paris-Saclay, DER de Physique, 91190, Gif-sur-Yvette, France

2)

Research Institute for Applied Mechanics, Kyushu University, Fukuoka 816-8580, Japan

(Received 4 August 2025 / Accepted 4 November 2025 / Published 21 January 2026)

Abstract

Runaway electron (RE) driven kinetic instabilities have been observed in the QUEST spherical tokamak. A strong correlation between decay of the plasma current and activity of kinetic instabilities was first found with quasi-periodic behaviour during current quench. An efficient mitigation of RE by interaction with kinetic instabilities was experimentally demonstrated.

Copyright (c) 2026 The Japan Society of Plasma Science and Nuclear Fusion Research

Keywords

runaway electron, kinetic instability, current quench, RE mitigation, spherical tokamak

DOI: 10.1585/pfr.21.1202010

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References

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