Simulation for spatio-temporal variation of chemically active species in an atmospheric pressure streamer discharge..

Spatiotemporal variation of radical density in an atmospheric pressure plasma discharge has been investigated by two-dimensional numerical simulation. Behaviors of radicals are characterized by four areas as ”Hot anode region”, “Secondary streamer region”, “Primary streamer region”, and “Near-cathode region”. Although the reduced electric field in ”Hot anode region” is relatively high, the gas temperature also increases and the ozone destruction process proceed. On the other hand, in “Near-cathode region”, the high-energy radicals such as N(4S) is effectively produced because the instantaneous value of reduced electric field is high. Behaiviour of OH is also investigated. The results show that OH is effectively produced in “Secondary streamer region” and is not effective in “Hot anode region”. This is because the reduced electric filed in “Secondary streamer region” is sufficiently high for the dissociation of H2O by O(D) and N2(a) and the gas temperature in “Hot anode region ” is too high for the production of OH.