Production of Monopolar Ions by Traveling Wave Corona Discharge

The production of monopolar ions by traveling wave corona discharge is investigated-using both a paralel wire and a double-helical wire electrode systems for developing the pulse-energized boxer charger applicable in large-scale ESP's. The traveling wave corona takes the form of streamers uniformly distributed on the wires and is enhanced by applying an external field to the wires. With decreasing pulse duration time and increasing wire-to-wire spacing, the corona becomes more stable, and its tendency to turn into spark is hampered. At an external field strength of 5 kV/cm, wire-to-wire spacing of 20 mm, and pulse duration time of 200 ns, it is possible to extract from the streamers the monopolar ionic current with a density of 0.6 mA/m2 along the entire length of a 10-m long electrode system. Such a short duration time also allows the use of the "inductance-isolation" concept for electrical insulation of the two wires from each other. An inductance of 25 AH provides a satisfactory insulating effect.