The manipulation of atmospheric pressure dielectric barrier plasma jets

Atmospheric pressure plasma jets offer a unique route to transport reactive chemical species generated under highly non-equilibrium conditions to a remote downstream sample; as such, they have become the device of choice in many biological and materials processing applications. This contribution explores techniques to manipulate the propagation dynamics of the fast moving ionization front generated in a dielectric barrier plasma jet, after it is launched from the powered electrode. To achieve this, the electric field in the region through which the ionization front propagates is manipulated on a sub-microsecond timescale. It is demonstrated that the application of voltage pulses of varying duration and delay to supplementary electrodes placed along the axis of propagation and tangential to it facilitates a considerable level of control over the velocity, intensity and direction of the ionization front. In doing so, the flux of reactive species transported to a specific point on a downstream substrate can be electrically modulated on a pulse to pulse basis, a finding that could significantly extend the application scope of plasma jet devices.