Estimation of the j x B Force Produced by Electron Cyclotron Heating in HSX Plasma

The force related to electron cyclotron heating (ECH) is investigated in HSX plasma. Radial diffusion of energetic electrons by ECH produces a canceling return current, which then generates a j x B force that can play an important role in the toroidal rotation during ECH in HSX plasma. We investigate the energetic electron distribution by ECH by applying GNET code, which can solve the 5D drift kinetic equation for the energetic electron. We evaluate the j x B force and the collisional force due to the friction of the toroidal drift motion of the energetic electrons. As a result, we obtained a significant force due to the ECH and found that a larger force is obtained in the Mirror configuration than in the quasi-helically symmetric (QHS) one. The magnitude relationship of the force is consistent with that of the experimental flow velocity. (C) 2019 The Japan Society of Plasma Science and Nuclear Fusion Research