A new type of the cold atmospheric plasma source for catalytic plasma treatment of gas is presented. The fused hollow cathode (FHC) source is based on simultaneous radio frequency (rf) generation of hollow cathode discharges in an integrated, open structure, with flowing gas. The resulting FHC discharge is very stable, homogeneous, luminous, volume filling, without streamers. The power consumption is very low, of the order of tenths of Watt per em(2) of the electrode structure area. Experiments for the hollow electrode integrated open structure up to 20cm(2) were performed. The concept of the source is extremely suitable for scaling up for different gas throughputs. The FHC source represents a new non-equilibrium atmospheric plasma source suitable for transformation of gas. Moreover, its design offers both catalytic reactions in the bulk of plasma and at solid surfaces composing the open structure.