Similarity law for rf breakdown

This paper demonstrates that the similarity law for the rf gas breakdown has the form U rf =ψ( p · L , L / R , f · L )(where U rf is the rf breakdown voltage, p is the gas pressure, L and R are the length and diameter of the discharge tube, respectively, f is the frequency of the rf electric field). It means that two rf breakdown curves registered for narrow inter-electrode gaps or in geometrically similar tubes and depicted in the U rf ( p · L ) graph will coincide only when the condition f · L =const is met. This similarity law follows from the rf gas breakdown equation and it is well supported by the results of measurements.