22 research outputs found
Influence of different processes of the electron emission on the ultrahigh charging of a dust particle in plasma by the energetic e-beam.
Role of the volume and surface breakdown in a formation of microdischarges in a steady-state DBD
The results of an experimental study on a spatial-time behavior of
microdischarges (MDs) in steady-state dielectric barrier discharge (DBD) are
presented. MDs of DBD have a spatial “memory”, i.e. every subsequent MD
appears exactly at the same place that was occupied by the preceding MD. In
most cases each MD appears at its fixed place only once by every half-period (HP). Spatial “memory” is derived from slow
recombination of plasma in the MDs channels for a period between two
neighbor HPs. In steady-state DBD each plasma column was formed only
one-time due to local avalanche-streamer breakdown in the very first
(initial) gas gap breakdown under inception voltage . After that
DBD is sustained under voltage lower than . For the
plane-to-plane DBD having the restricted electrode area there is a critical
voltage U1: DBD is in a steady-state if U > U1 but the DBD decays
slowly at voltages below U1. The decay takes many HPs and occurs due to
decreasing the number of MDs inside the gap because of their Brownian motion
from central region to the outside of the discharge area. In steady-state
DBD there is no correlation between an appearance of alone MD and phase of
the applied voltage – each MD has a great scatter in its appearance at the
HP. This scatter is attributed to the dispersion in a threshold voltage for
local surface breakdowns around the MD base. So, in steady-state DBD the MD
volume plasma is responsible for an existence of spatial “memory” (i.e.
where the MD appears) but the surface charge distribution around MD
is responsible for MD time dispersion (i.e. when the MD appears)