In order to obtain the influence of electrode structure（electrode length and electrode angle） on the size of the discharge plasma of the gliding arc

a gliding arc discharge（GAD） device which is easy to replace electrodes is designed. An oscilloscope was adopted to measure the electrical signal of the gliding arc discharge plasma

and the images of gliding arc discharge with the electrodes of different structures are taken by a high-speed cemera and DV cemera. The results show that

with the increase of flow rate

gliding arc discharge has three different states. The voltage waveform of the steady GAD plasma is a waveform whose peak value is gradually increasing

which is distinct from the voltage waveform of the traditional AC arc. When the power and the flow rate are constant

the length of plasma will decrease with the increase of the length of the electrodes. And the plasma cannot exceed the end of electrodes when the length of the electrodes reaches 50 mm. The width of plasma width reaches the maximum when the electrode length is 20 mm. When the length of the electrode is 20 mm

the gliding distance of the arc along the electrodes will decrease with the increase of opening angel of electrodes

which results in the reduction of the size of the GAD plasma.