A Magnetic Field Induced Cold Atmospheric Pressure Air Plasma Jet

Cold atmospheric pressure plasma jets (APPJs) using air as working gas are of particular interest and desirable but with significant challenge. In this article, an air APPJ induced by an external radial magnetic field is reported. The experimental results show that with the external magnet, an air plasma jet can be obtained with a length of 7 mm and a width of 10 mm. While without the external magnet, the plasma only exists in the dielectric tube. The dynamic behavior shows that its propagation velocity is close to the gas flow velocity. The plasma jet appears no difference when it is in contact with a ground conductive object. On the other hand, optical emission spectrum shows that they are dominated by the N2 and $\text{N}_{2}^{+}$ emission. The electrical characteristic shows that the peak of the discharge current and the breakdown voltage increase when the magnet is used. The gas temperature of the plasma jet is about 310 K. Laser-induced fluorescence measurement shows that high concentration of OH radicals appears along the plasma jet. In the sterilization experiment, the application of external magnetic field has increased the sterilization effect by about two times