Development of an RF plasma source using helicon waves for the study of plasma-material interactions in fusion machines

A plasma source using a Nagoya type III antenna surrounding a 30-cm-long glass tube attached to a 1.5-m-long cylindrical chamber to excite helicon waves has been developed. The plasma is confined by an axial magnetic field in the range of 0.2-1 kG generated by a pair of Helmholtz coils located at both ends of the chamber. A plasma density of about 10 12 cm -3 is obtained with an electron temperature of about 10 eV. The chemical sputtering of graphite by an oxygen plasma was studied using this plasma source