Luminous Discharge Between Lecher Wires in a Partially Evacuated Tube

Abstract

In experiments with a Gill-Morrell oscillator generating undamped waves less than a meter in length, a study was made of the potential difference between the Lecher wires coupled to the oscillator by enclosing these wires in an evacuated glass tube several wave-lengths long. The oscillator itself employed two type −52 tubes connected in push-pull and it set up radiofrequency currents of 2.5 amperes in the Lecher wires and potential differences in excess of several hundred volts between the wires at positions separated by half wave-length intervals. At these voltage loops for certain critical pressures, between the wires a discharge took place which was photographed as well as employed in a direct study of the standing waves in the wires. The gases used in the tube were air, helium, oxygen, mercury vapor and mixtures of these gases with air. The use of this tube made possible a visual study of the changes in potential distribution as various circuit adjustments were made. A series of double maxima was observed as the length of the line was changed by a half wave-length.