Physical processes in duplexer discharges in chlorine and oxygen

The high-power properties of the input-window discharge of a TR tube are analyzed in terms of the transmission and reflection coefficients of a thin plasma slab terminated by a low-intensity secondary gap discharge. Computer solutions were obtained for equations expressing the TR properties of arc loss, leakage power, recovery time, and phase shift as functions of collision frequency and electron density. Measurements of arc loss and leakage power in a chlorine discharge yielded values of electron density of 1 × 10
¹⁴
to 6 × 10
¹³
electrons/cm
³
over a 0.5- to 80-torr pressure range. The recovery period at
X
-band corresponds to a decaying plasma in which electron density decays from 10
¹⁴
to 10
¹²
electrons/cm
³
. This decay occurs in less than 0.5 µs for chlorine discharges. An analysis of the physical mechanisms controlling fast recovery times in electronegative gases shows that the two most important physical mechanisms are recombination of electrons and ions in the early recovery period and electron attachment in the late recovery period. Experimental data is presented for the recovery of chlorine and oxygen over a pressure range of 0.5 to 80 torr. An analysis of measured values of attachment frequency in oxygen indicates that the electron temperature in the recovery period, which is early in the afterglow, was in the 1.4- to 1.2-eV range.