Determination of the electron density in a discharge with nonmetallic liquid electrodes in atmospheric-pressure air from the absorption of microwave probe radiation

Measurements were made of the absorption of microwave power in a discharge plasma generated using tapwater electrodes in atmospheric-pressure air in order to determine the electron density. The high-voltage discharge burned in a bulk (diffuse) form with a lower current density than an are discharge. This type of discharge with nonmetallic liquid electrodes is extremely promising for various technical applications. Regimes with I=50-60 mA and voltages U=2.9-3.1 kV were studied. The measurements were made at probe radiation frequencies F = 29.6 and 35.2 GHz. A two-conductor transmission line was used to localize the microwave power in the plasma. An estimate was obtained for the average electron density in the central part of the discharge (4 X 10(11)) < n(e) < (7 X 10(11))cm(-3). This result shows good agreement with the results of earlier probe measurements. (C) 1998 American institute of Physics. [S1063-7850(98)01012-X].