Nanosecond pulse discharges in C3F8‐Ar mixtures

摘要

In this paper we present results from experiments to determine the behavior of C3F8‐Ar mixtures as filling gases in a uniform‐field spark gap subjected to high voltage, nanosecond pulses. The gas pressure ranges from 500 to 960 Torr and the overvoltage ranges from 50% to 300%. The electrode separation is 1 cm. U‐V irradiation has been used prior to the arrival of the pulse to the gap. In general, the discharge consists of very large numbers of closely packed filaments with the overall diameter being less than or equal to approximately 1 cm. The initial rate of current rise at the load is large (∼1012 A/sec). Subsequently, a phase of relatively constant current is observed the length of which changes with the concentration of C3F8. This phase has large resistance and the energy deposited into the discharge ranges from 6% to 20% of the energy in the incident pulse, as the concentration of C3F8 increased from 30% to 100%. The final state of conduction of the discharge is an arc. In light of these observations, the behavior of self‐ and nonself‐sustained discharges is discussed.