Optimum Configuration and Operation Regime of Pumped Limiter in INTOR

摘要

A detailed recycling model of neutral particles on the limiter surface and first wall in the one-dimensional tokamak transport code are developed. The energy of neutral particles, which flow back from the limiter chamber, is calculated by the two-dimensional Monte-Carlo neutral code, and is incorporated into the tokamak code. The optimum configuration and operation regime of the pumped limiter in INTOR are obtained. The main conclusions obtained are (1) the electron temperature in the scrape-off layer plasma decays rapidly, while the density distribution is fairly broad, (2) a considerably long limiter with a moderate pumping speed is sufficient to keep the helium accumulation in the main plasma at a desired level, (3) overall particle confinement time for helium becomes much longer than that for fuel particles, (4) the minimum amount of tritium pumped out little depends on the limiter length, if the pumping speed is appropriately adjusted so as to keep the helium accumulation at the same level, (5) the electron temperature at the boundary is 400 -- 500 eV when the fueling is performed by the realistic pellet injection or gas-puffing, (6) although the high temperature operation regime (700 -- 900 eV) can be realized by large pumping and ideal pellet injection with short limiter length, this regime will not necessarily be preferable if the heat flux and erosion of the leading edge are more critical for the engineering. (Atomindex citation 15:051147)