Fabrication of prototype ICRF antenna for KSTAR and first RF test

摘要

A prototype ICRF antenna has been fabricated and is being tested for the development of long pulse (300 s), high power ICRF system of KSTAR. The antenna has many cooling channels inside the current strap, Faraday shield, cavity wall and vacuum transmission line to remove the dissipated RF loss power and incoming plasma heat loads. The antenna is installed in the RF test chamber evacuated by 2000 l/s turbomolecular pump and consistency with the design requirement for long pulse, high power operation is being investigated through the RF test. With the half of a current strap connected to the matching circuit via a vacuum feedthrough and a directional coupler, and the other seven ports shorted at the input ports, intermediate RF power test has been performed at f= 32 MHz. During the RF pulse, the maximum peak voltage, forward/reflected powers, temperature on the antenna and gas pressure are measured. Even the initial test results promise that the long pulse, high power operation of the ICRF system will be obtainable for the advanced tokamak operation of KSTAR tokamak.