Power Balance in TOKASTAR-2 Small Tokamak for Feasibility Study on Light Source Application

An application of small tabletop tokamak as light source is considered. Temporal evolution of the electron temperature and density is measured using passive spectroscopy applicable for small low temperature tokamaks. Ion temperature measurement is also performed. Those are applied to the smallest tokamak, TOKASTAR-2, major radius of which is \(R_0\simeq 0.1\,\textrm{m}\) . The stored energy is determined from the temperature and density measured in the tokamak. Energy confinement time deduced from the temperature and density is comparable with a scaling law for larger tokamaks. Line radiation power is evaluated from direct measurement and a collisional radiative model calculation based on the measured temperature and density. These clarifies the power balance in TOKASTAR-2. Neutral depletion during tokamak operation is suggested. Resonant EUV line radiation is estimated from measurement data.