The thermoelectric instability in tokamak divertor has been studied numerically by using a five-point model. When the divertor plasma temperature Tdiv decreases below a critical temperature, this instability arises in a symmetric equilibrium of scrape-off layer (SOL) and divertor plasmas, and stable asymmetric equilibria are found. The SOL current causes spontaneously the divertor asymmetry at the onset of the thermoelectric instability. In an asymmetric equilibrium, the SOL current flows from the higher-Tdiv side to the lower-Tdiv side. The heat flux flowing into the divertor plate of the higher-Tdiv side becomes larger than that of the lower-Tdiv side. The heat flux asymmetry is larger for cases of high recycling and low heating power.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials