@article{oai:repo.qst.go.jp:00084811,
 author = {Takahiro, Bando and Mitsuru, Honda and Shizuo, Inoue and Maiko, Yoshida and Go, Matsunaga and Akihiko, Isayama and Manabu, Takechi and Koji, Shinohara and Shuhei, Sumida and Takahiro, Bando and Mitsuru, Honda and Shizuo, Inoue and Maiko, Yoshida and Go, Matsunaga and Akihiko, Isayama and Manabu, Takechi and Koji, Shinohara and Shuhei, Sumida},
 issue = {11},
 journal = {Plasma Physics and Controlled Fusion},
 month = {Nov},
 note = {In the JT-60U tokamak, low frequency modes (LFMs) have been reported recently when the m/n = 2/1 neoclassical tearing mode grows sufficiently. LFMs show the low mode frequencies (<20 Hz) with the rotation direction to the counter-current direction (ctr-direction) toroidally, even if strong injection power to the co-current direction (co-direction) is applied by tangential neutral beam injections. As a candidate to drive the rotation to the ctr-direction, the neoclassical toroidal viscosity (NTV) torque is investigated in this study. Indeed, when a LFM is observed, the estimated 'offset velocity' of the NTV torque is larger than the observed toroidal velocity around the q = 2 surface and results in the torque to the ctr-direction (ctr-torque). The torque balance between the NTV torque and the torque induced by the eddy current on the resistive wall is investigated. It is found that the rotation to the ctr-direction having the low mode frequency is obtained as the result of the ctr-torque to the offset velocity. Our investigation suggests the requirement to include the NTV torque in the modeling on the mode locking of neoclassical tearing modes in tokamaks.},
 title = {Torque to counter-current direction driving low frequency tearing modes in JT-60U},
 volume = {63},
 year = {2021}
}