  The axial light distributions in parallel-plate dc microdischarges in argon
show similar behavior to large scale discharges. Between the low-current
Townsend mode and the high current glow mode exists a large region of currents
where different oscillations appear and the dynamic Volt-Ampere characteristic
shows hysteresis behavior. During the oscillations the maximum peak intensity
moves closer to the cathode, which is characteristic for the abnormal glow
regime even though the average current is considerably smaller.
