"Snowflake" H Mode in a Tokamak Plasma
An edge-localized mode (ELM) H-mode regime, supported by electron cyclotron heating, has been successfully established in a snowflake (second-order null) divertor configuration for the first time in the TCV tokamak. This regime exhibits 2 to 3 times lower ELM frequency and 20% 30% increased normalized ELM energy ($Delta W_{ELM}/W_p$) compared to an identically shaped, conventional single-null diverted H mode. Enhanced stability of mid- to high-toroidal-mode-number ideal modes is consistent with the different snowflake ELM phenomenology. The capability of the snowflake to redistribute the edge power on the additional strike points has been confirmed experimentally.
1002508.pdf
openaccess
1.97 MB
Adobe PDF
802e71138fe1895b1b31f73829d11d6a