Impact of applied voltage, air gap, and ground arrangement on discharge power and dielectric capacitance in a volume DBD plasma

Abstract Electrical parameters such as total equivalent capacitance, dielectric capacitance, and average discharge power of a dielectric barrier discharge (DBD)-cold atmospheric plasma (CAP) setup have been determined and their dependency on the applied voltage, air gap, and ground arrangement have been investigated. Considering a more practical scenario of DBD-CAP application in material processing and biomedical fields, three different ground arrangements: (i) bare ground, (ii) glass slide covered ground and (iii) water in a petri dish on the ground electrode have been considered in this study. The electrical parameters are determined by interpreting the charge-voltage (Q-V) plot of the DBD-CAP obtained experimentally. The value of effective dielectric capacitance ( ζ d ) determined from Q-V plot at a lower applied voltage is less, and approaches the geometrically calculated value ( C d ) at higher applied voltage which signifies the DBD discharge occurs from the partial area of the electrode surface. Discharge power and discharge efficiency increase with the applied voltage ( V a ). Empirical fit of the obtained discharge power shows the increase is proportional to <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msup> <mml:mrow> <mml:mo stretchy="false">(</mml:mo> <mml:msub> <mml:mrow> <mml:mi>V</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>a</mml:mi> </mml:mrow> </mml:msub> <mml:mo>−</mml:mo> <mml:mi>B</mml:mi> <mml:mo stretchy="false">)</mml:mo> </mml:mrow> <mml:mrow> <mml:mn>2</mml:mn> </mml:mrow> </mml:msup> </mml:math> , where the value of constant B is close to the value of threshold voltage for the discharge.