[Study on spatial distribution of electron energy in hollowneedle-plate dielectric barrier discharge]

In the present work, the spatial distributions of spectrum intensity of molecule and atom in the plasma generated in hollowneedle-plate discharge in atmosphere were measured, and the spatial distribution of electron energy in plasma was analyzed. A plasma about 3 cm long is generated by using a hollowneedle-plate discharge device. By collecting optical emission spectrum from 300 to 800 nm, it was found that the spectrum consists of strong Ar I lines, strong second positive band system of N2, and weak OI line. The spatial distributions of spectrum intensity of Ar I (696.54, 763.51, 772.42, and 794.82 nm), band N2 (337.1, 357.6, and 380.4 nm), and OI 777.2 nm were measured. The Ar I lines decreased gradually from the arc root. The N2 lines increased gradually from the arc root and declined when they reached a maximum at 12 mm away from the arc root. The intensity of OI increased from the arc root and declined when it reached a maximum at 6 mm away from the arc root. The spatial distribution of electron energy in plasma was analyzed qualitatively from the spatial distribution of spectrum intensity given above. It was found that the electrons located at 6 mm away from the are root have high energy, while they have low energy at arc tip.