Transient phenomena during dense argon micro-plasma formation

We report on transient generation of highly ionized (ionization degree ∼10%) argon microplasma using a self-consistent fluid plasma model coupled with the compressible Navier–Stokes equations. The plasma is generated within a micrometer size cathode spot immediately after the onset of intense secondary electron emission from the cathode and exists over a relatively short duration of ∼10 ns. We observe the electron pressure within this microplasma exceeding the background gas pressure by a few times and discuss the mechanisms of the energy transfer from this plasma to the heavy species. The localized gas heating generates a compression wave that propagates from the cathode to the anode.