Measurements of fast-ion losses induced by MHD instabilities using a scintillator-based probe in the HL-2A tokamakaContributed paper, 25th IAEA Fusion Energy Conf. (Saint Petersburg, Russia, 13–18 October 2014) EX/P7-24. (5th October 2015)

• Record Type: Journal Article
• Authors: Zhang, Y.P.; Liu, Yi; Chen, W.; Xu, Y.; Isobe, M.; Li, D.; Ji, X.Q.; Dong, Y.B.; Ding, X.T.; Yuan, G.L.; Yang, J.W.; Song, X.Y.; Li, X.; Song, X.M.; Yan, L.W.; Yang, Q.W.; Duan, X.R.
• Other Names: collab.
• Is Part Of: Nuclear fusion. Volume 55:Number 11(2015:Nov.)
• Publication Date: 2015-10-05
• Subjects: fast ion -- fast-ion loss probe -- MHD -- NBI -- tokamaks; Nuclear fusion -- Periodicals; 621.48405
• DOI: 10.1088/0029-5515/55/11/113024
• Languages: English
• ISSNs: 0029-5515

Abstract

Abstract: Characteristics of fast-ion losses induced by various magnetohydrodynamic (MHD) instabilities, such as tearing mode (TM), long-lived mode (LLM), and sawtooth crash, have been observed and experimentally investigated in the HL-2A tokamak. To study fast-ion losses, a new scintillator-based lost-fast ion probe has been developed and used, and an increment of the fast-ion loss rate as the MHD amplitude increase has been measured. Compared with TM and LLM, the fast-ion losses induced by sawtooth crash have a broad range in energy and pitch angle. There may be some interactions between fast ions and magnetic disturbance, which cause the losses with a wide range of energy and pitch angle. During disruptions, the total neutron emission rate drops by ~90% as a result of the strong fast-ion losses. The possible reasons for this phenomenon are the strong magnetic perturbations and the drastic change of the fast-ion transport. In addition, the clear experimental evidence of drastic losses of fast ions during disruptions have been obtained.