The AC gliding arc induced by a weakly ionized gas flow between two sword-shaped electrodes was investigated.The effects of inlet gas flow rate and distance between electrodes on such physical parameters as discharge voltage

current

power

and convective heat transfer were studied.The results show that the discharge voltage increases with arc length extending when the gas flow rate is low（e.g.0.9 L/min）

and the voltage becomes unstable in the place where the arc is short when the gas flow rate is high（e.g.over 10 L/min）;the discharge power increases linearly with gas flow rate at first and then keeps constant

while the specific power per unit decreases with gas flow rate.Therefore

the gliding arc can be divided into three stages corresponding to low

medium

and high gas flow rate

and the medium gas flow rate（10～35 L/min） is suitable for chemical process.In every half period

instantaneous discharge power changes sinusoidally

and convection contributes to the main heat loss.Based on these results

the equilibrium and non-equilibrium characters of the gliding arc can be analyzed quantitatively.When the instantaneous discharge power is larger than the convective heat transfer

the arc is in equilibrium

or reversely it is in non-equilibrium.