Initial Plasma Confinement Experiments in Tokamak-Helical Hybrid Device TOKASTAR-2

抄録

A tokamak-helical hybrid device TOKASTAR-2 with outboard helical field coils located outside the toroidal field coil system was constructed. Initial plasmas are produced by the electron cyclotron heating scheme, and the plasma electron density profile is measured using electrostatic double Langmuir probes. The peak location of measured electron density profile in the radial direction agrees with the first electron cyclotron resonance layer at initial beak-down period and at final disappearance period of the plasma discharge. The suppression of bursting electron density oscillations and the shift of plasma density profile are observed in the case of applying outboard helical magnetic field.