Schlieren Photography of the Outflow From a Plasma Jet

Using Schlieren photography, the helium outflow configuration from a fine capillary-based microplasma jet discharge has been captured for free-stream conditions. The transition from laminar to turbulent flow is clearly identified with and without operation of the plasma. At a flow rate of 2.3
$ \hbox{L}\cdot\hbox{min}^{-1}$
with no plasma operating, this transition occurs 54 mm from the nozzle; however, with plasma struck (peak voltages of 8
$\hbox{kV}_{{\rm p}-{\rm p}}$
), this reduces to 40 mm.