Phase switching dynamics between three inductively coupled glowdischarge plasma sources

The phase switching dynamics is studied between three inductively coupled glow discharge plasma sources. For this, DC glow discharge plasma is produced in three separate glass chambers of same configuration. Due to the asymmetry in the sizes of the electrode areas, anode glow is formed in each of the systems which in turn produces the oscillations in the plasma. The plasma parameters in three systems are adjusted such that the oscillation frequencies of these systems are 242, 216 and 268 kHz respectively. Firstly, inductive coupling is provided between the systems with oscillation frequencies of 242 and 268 kHz. It has been observed that the oscillation frequencies of two systems goes to a anti-phase synchronized state with a frequency of 199 kHz. After that, third system with oscillation frequency of 216 kHz is inductively coupled with these two systems. It has been observed that with this coupling oscillations of previously coupled systems switches from anti-phase state to in phase state with a coupling frequency of 185 kHz. Also, these experimental observations are numerically modelled using three environmentally coupled Van der Pol oscillators and the obtained results are found to be in good agreement.