ELECTRON-CYCLOTRON-RESONANCE PLASMA IN MULTICUSP MAGNETS WITH AXIAL MAGNETIC PLUGGING

An electron cyclotron resonance plasma source is built by arranging SmCo magnets to form a multicusp magnetic field with axial magnetic plugging. The source is tested in H2, N2, and Ar by the microwave of 2.45 GHz in the range from 10-2 to 10-3 Pa. The discharge sustaining power is measured as a function of pressure. The plasma density, the average electron energy, and the electron energy distribution are measured by using a Langmuir probe. Plasma is obtained at pressures as low as 10 -3 Pa in Ar. The average electron energy and the ion density increase with the feed microwave power. The electron energy distribution shows depletion at the low-energy part. Ion spectra obtained in Ar show a multicharged state up to Ar8+. © 1994 American Institute of Physics.