Argon Ion and Neutral Metastable Levels Destruction in a Magnetically Enhanced Inductively Coupled Plasma Reactor

This paper deals with pure argon plasma studied in a magnetically enhanced inductively coupled reactor. Laser induced fluorescence technique was performed with an optical parametric oscillator laser on the 3d 4F7/2 and 3d 2G9/2 Ar + metastable levels and on the (2P3/2 0 )4s neutral metastable state to determine their relative densities. Langmuir probe was used as a complementary diagnostic to measure the electron energy distribution functions. When increasing the confinement magnetic field, the metastable state density collapses for all cited levels, by contrast with ne which is continuously growing. Calculations were carried out for neutral argon to explain this behaviour. The results show that the metastable population is depleted by electron-impact excitation and ionization, these loss processes becoming dominant compared to the metastable state creation term.