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 arc 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 (4×1011)<ne<,(7×1011)cm−3. This result shows good agreement with the results of earlier probe measurements.