Experimental investigation of near anode phenomenon in inverted cylindrical magnetron discharge

The experimental investigation of the plasma properties near the anode of an inverted cylindrical DC magnetron discharge is carried out in the background of argon gas. These experiments are mainly performed at the low transverse magnetic field in the range of 0–100 G and at an argon pressure of 0.3–2 × 10−2 mbar. It is observed that the anode fall becomes prominent in the presence of a magnetic field. In addition, the plasma potential profile near the anode shows two distinct regions with potential difference of 10–15 V at the boundary of anode glow. It is also noticed that the anode glow expands radially as a function of magnetic field. The size of the anode glow increases with magnetic field in order to collect more electron current. The plasma density and electron temperature as measured by the double Langmuir probe near the anode are observed to be higher as compared to the background plasma. The stable electron sheath near the anode transforms into oscillating anode glow with the application of magnetic field beyond 4–5 G. The oscillation frequency as observed in floating potential and discharge current lies in the range of 1–10 kHz. The frequency increases linearly with discharge power and argon pressure while it decreases with magnetic field. Furthermore, a qualitative interpretation of the inverted cylindrical magnetron discharge is provided based on the theoretical analysis performed by Golubovskii et al.