Fig. 3From: Schlieren imaging: a powerful tool for atmospheric plasma diagnosticNumerical simulations of (a) the axial velocity Vz (ms− 1) and (b) helium mass fraction Y, compared with (c) an experimental schlieren image, for 1.5 slpm of He flow rate and the plasma in operation (20kVp-p). Schlieren imaging was performed in a Z-type configuration setup with a high-power green light-emitting diode, two spherical mirrors and a Foucault knife-edge tester [44] © Deutsche Physikalische Gesellschaft. Reproduced by permission of IOP Publishing. CC BY-NC-SABack to article page