Development of a helicon-wave excited plasma facility with high magnetic field for plasma-wall interactions studies

摘要

The high magnetic field helicon experiment system is a helicon wave plasma (HWP) source device in a high axial magnetic field (B0) developed for plasma-wall interactions studies for fusion reactors.This HWP was realized at low pressure (5 × 10 3-10 Pa) and a RF (radio frequency,13.56 MHz) power (maximum power of 2 kW) using an intemal right helical antenna (5 cm in diameter by 18 cm long) with a maximum B0 of 6300 G.Ar HWP with electron density ～1018-1020 m-3 and electron temperature ～4-7 eV was produced at high B0 of 5100 G,with an RF power of 1500W.Maximum Ar+ ion flux of 7.8 × 1023 m-2 S-1 with a bright blue core plasma was obtained at a high B0 of 2700 G and an RF power of 1500 W without bias.Plasma energy and mass spectrometer studies indicate that Ar+ ion-beams of 40.1 eV are formed,which are supersonic (～3.1 cs).The effect of Ar HWP discharge cleaning on the wall conditioning are investigated by using the mass spectrometry.And the consequent plasma parameters will result in favorable wall conditioning with a removal rate of 1.1 × 1024 N2/m2h.