Generation of micrometer-scale discharge in a supercritical fluid environment

Abstract

The generation of micrometer-scale discharge in very high-pressure CO2 up to a supercritical fluid (SCF) environment using micrometer-gap (1, 2 μm) electrodes has been performed. A peculiar characteristic of breakdown voltage for CO2 is reported here. The results reveal an inflection near 2.5 MPa and a trough near the critical point. Near the critical point, the discharge can be generated with almost one fifth of the voltage required for a conventional gas, as estimated from Paschen’s law, which is probably caused by unstable clusters in SCF. This result reveals that an ionized state or plasma state in a SCF environment can be generated with very low voltage.