Fully non-inductive second harmonic electron cyclotron plasma ramp-up in the QUEST spherical tokamak. (5th October 2017)

• Record Type: Journal Article
• Authors: Idei, H.; Kariya, T.; Imai, T.; Mishra, K.; Onchi, T.; Watanabe, O.; Zushi, H.; Hanada, K.; Qian, J.; Ejiri, A.; Alam, M.M.; Nakamura, K.; Fujisawa, A.; Nagashima, Y.; Hasegawa, M.; Matsuoka, K.; Fukuyama, A.; Kubo, S.; Shimozuma, T.; Yoshikawa, M.; Sakamoto, M.; Kawasaki, S.; Nakashima, H.; Higashijima, A.; Ide, S.; Maekawa, T.; Takase, Y.; Toi, K.
• Is Part Of: Nuclear fusion. Volume 57:Number 12(2017:Dec.)
• Publication Date: 2017-10-05
• Subjects: electron cyclotron heating and current drive -- electron Bernstein wave heating and current drive -- spherical Tokamak -- non-inductive plasma startup; Nuclear fusion -- Periodicals; 621.48405
• DOI: 10.1088/1741-4326/aa7c20
• Languages: English
• ISSNs: 0029-5515

Abstract

Abstract: Fully non-inductive second (2nd) harmonic electron cyclotron (EC) plasma current ramp-up was demonstrated with a newlly developed 28 GHz system in the QUEST spherical tokamak. A high plasma current of 54 kA was non-inductively ramped up and sustained stably for 0.9 s with a 270 kW 28 GHz wave. A higher plasma current of 66 kA was also non-inductively achieved with a slow ramp-up of the vertical field. We have achieved a significantly higher plasma current than those achieved previously with the 2nd harmonic EC waves. This fully non-inductive 2nd harmonic EC plasma ramp-up method might be useful for future burning plasma devices and fusion reactors, in particular for operations at half magnetic field with the same EC heating equipment.