The air arc is a common plasma

and the study of its microscopic parameters in the steady state stage is of great significance for accurately grasping the reaction mechanism inside the plasma. Emission spectroscopy is a mature technique for diagnosing plasma electron density

which has such advantages as non-contact measurement

transient detection

high sensitivity

fast response

and simple instrumentation. In this paper

the

H

α

656.28 nm spectral line is used as the characteristic spectral line

and graphite is used as the electrode material to

measure the emission spectrum of the air arc under the conditions of 250 A and 200 V. Abelian inverse transformation and Viogt off-line fitting are performed on the emission spectrum obtained from the experiment

Stark broadening is obtained by deconvolution

and finally the radial distribution of the air arc electron number density is obtained. At the same time

the Thomson scattering method is used to measure the electron number density of the air arc under the same parameter conditions to verify the correctness of the emission spectrometry measurement results. It is verified that the measurement results of the two methods have good consistency. This experiment provides a reference idea and method for the measurement of air arc plasma electron number density.