Study of RF Source Ignition System with Impedance Matching Network for RF Driven H- Ion Source
This paper presents study of a 6.78 MHz RF source with impedance matching network based inductively coupled plasma generator ignition system for an H- ion source. Two types of 10 turn RF antenna (solenoid coil) were developed, to couple the RF power to the ignition plasma chamber. The antenna’s electric parameters were measured using Vector Network Analyzer (VNA). A copper conductor of 3 x 4 mm size with 10 turn solenoid coil was selected for simulation and experimental prototype antenna. Two L-types of (CCL and LCL C-capacitor and Linductor) matching network were selected for impedance matching network for RF antenna. Initial simulations are carried out using ELSIE and LT-spice for frequency range from 5 to 8MHz. The matching network along with RF antenna was matched to ~ 50 Ωimpedance at 6.78 MHz with capacitive nature. An experimental prototype RF power source, 10 turn antenna (coil) and a matching network was developed to validate the simulation results. The prototype ignition system along with impedance matching network L-type with CCL was tested for inductively coupled hydrogen plasma generation and experimental results presented. Hydrogen plasma generation starts at minimum antenna coupled RF power of 150 watts, once initiated hydrogen plasma maintains to a minimum RF power of 10 watts.