An atmospheric pressure argon direct current microplasma discharge apparatus was built using a stainless steel capillary as the cathode

a stainless steel mesh as the anode.The voltage-current characteristics were measured

and different modes of discharge

hollow cathode discharge and abnormal glow discharge

were observed.It is shown that the voltage-current characteristic is similar to the known characteristic of low pressure glow discharge.The dependences of discharge voltage on gas pressure and argon flow rate were investigated.The experimental results show that the discharge voltage decreases when the gas pressure increases

and the dependence of discharge voltage on gas flow rate exhibits different characteristics

i.e.discharge voltage decreases first with gas flow rate

and then increases.