Distribution of OH within silent discharge plasma reactors

Barrier discharges in humid air generate large quantities of OH and are well suited for the treatment of gas-based pollutants, In order to understand and optimize the formation and utilization of OH, we have imaged the spatial and temporal distribution of the OH radical with resolution of 40 mu m and 100 ns. Using a flowing mix of Ar/O-2/H2O (78.5/20/1.5), we have found that OH exists only within the 85-mu m radius channel formed by the transient microdischarge. At modest power densities of 0.1 W/cm(2), over 10(6)/cm(2)/s of these small filaments quickly fill the entire reactor volume.