Startup of Plasma Current in J-TEXT Tokamak Prompted by the H-alpha Line Emission Criterion

摘要

An H-alpha line-emission detection system was developed on the joint texas experimental tokamak (J-TEXT), which is used to determine the H-alpha emission level during the gas breakdown and hereafter to control the startup of the plasma current. The detector consists of an H-alpha interference filter, a focusing lens, a photodiode and a preamplifier. In the J-TEXT operation, the H-alpha emission is taken as a monitor signal which is highly sensitive to the generation of a plasma. Furthermore, the power supply control system using the above signal as an input is capable of determining whether and when to fire the Ohmic heating capacitor banks, which are applied to drive the plasma current ramp-up. The experimental results confirm that the H-alpha emission criterion is acceptable for controlling the plasma current promotion in the J-TEXT tokamak.