Ion cyclotron heating experiments and plans for the Advanced Toroidal Facility (ATF).

摘要

Toroidal Facility (ATF) Ion Cyclotron Resonant Frequency (ICRF) experiments to date, a single-strap tunable antenna with carbon limiters has been used at power densities up to 13.6 MW/m(sup 2) (900 kW). Hydrogen minority heating experiments at 14.4 MHz were performed in deuterium plasmas formed initially with both second-harmonic electron cyclotron heating (ECH) and helium neutral beam injection (NBI). No ICRF heating was observed in the low-density ECH target plasmas. Two distinct NBI plus ICRF operating modes are described. The moderate heating of these discharges is probably limited by impurities sputtered from the vessel walls and/or poorly confined orbits for the heated particles. A two-strap, phased antenna, designed to reduce impurities and capable of both minority and direct electron heating is described. A second antenna design for optimizing the coupling to well confined ion orbits, additional ICRF heating schemes, and methods for reducing the RF edge interactions in a stellarator geometry are also being considered.