Atmospheric-pressure microplasmas with high current density confined inside helium-filled hollow-core fibers

Abstract

We report on the generation and confinement of atmospheric-pressure microplasmas inside the 100-to-2000-μm-inner-diameter (i.d.) hollow-core fibers (HCFs) filled with helium gas. The microplasma propagation inside these 10-cm-long HCFs results from the anode-driven pulse discharges with their durations of 30 ns–15 μs. The pulse current density generated at an i.d. of 100 μm is about four magnitudes higher than the glow-like one at an i.d. of 2000 μm. Analysis shows that the generation of the microplasmas with high current density can be explained by the confinement mechanism of HCFs with small i.d. values and low surface recombination rate.