Plasma production in the Hanbit magnetic mirror device by radio frequency waves

We report the plasma production experiment in the central cell of the Hanbi t device. In the experiment, an RF wave is excited by a slot antenna with a driving frequency of 3.75 MHz, and the RF power is applied up to 200 kW wi th a hat-top pulse length of 100 ms. The reproducible plasmas are produced without preionization with an averaged density of 2x10(12) cm(-3). The powe r absorption characteristics of the slot antenna are investigated by measur ing the plasma resistance; The measured value of plasma resistance is in th e range of 0.2 to 1.2 Omega. The discharges show transitions of the plasma density as the RF power increases.