The mesh tube has a sense it is no coincidence that it is put inside.
The operational cycle of the device, illustrated in the diagram, consists of two stages.
Initially, a discharge is produced between mesh tube (3) and the
dielectric (2) by a high voltage pulse applied to electrode (1).
Electrons flow to the dielectric and charge it Negatively,
thereby terminating the discharge. In this way, a temporary
or virtual cathode is formed on the dielectric surface.
During the second stage, the dielectric-covered electrode
(1) is switched to ground potential and a new discharge will
start. The electrons are now accelerated in the thin layer of
the cathode fall region, thereby Gaining an energy linearly
proportional to the applied voltage. The accelerated electrons
are subsequently emitted from the DBD region via a perforated
mesh tube.