A diffusion-cooled gas laser system that includes a first and a second electrode and a discharge gap arranged between the electrodes, wherein a dielectric is arranged on at least one of the electrodes on the discharge-gap side. The system is characterized in that the dielectric thickness d/∈res the dielectric for influencing the discharge ∈res of distribution in the discharge gap varies along at least one dimension of the electrode on which the dielectric is arranged, wherein d is the thickness of the dielectric, and ∈res is the resultant constant of the dielectric, and, at its thickest point, has a thickness of at least 1 mm or is greater than one hundredth of the length of the electrode or is greater than one thousandth of a wavelength determined by the frequency of a radiofrequency electrical power to be coupled into the system.