Movie S2.

Effect of high electric potential on the plasma stability and viability. The movie was taken from the impinging side and shows that the application of a 50-kV potential between the wafer and the nozzle, either positive or negative, leaves the plasma structure unaffected. The luminescence was generated in a mixed atmosphere of air and helium. Secondary streamers are seen that bridge the nozzle to the wafer away from the luminescent structure at the jet impingement site. They are not connected and do not interfere with this latter phenomenon.