Spectroscopic diagnosis of gas temperature in blown-out plasma of atmospheric-pressure microwave oxygen plasma torch

Abstract

The gas temperature of atmospheric-pressure microwave oxygen plasma torch in a blown-out plasma is diagnosed by optical emission spectroscopy (OES) via the atmospheric band O2(b1Σg+ →X3Σg−). The variations of gas temperature with respect to input power and gas flow rate are investigated, as well as the spatial distribution of gas temperature along the blown-out plasma. And the limitation of OES diagnosis in the experiment is discussed extensively. Moreover, the morphology of plasma torch is also inspected at various gas flow rates and values of microwave power.