This work is devoted to investigation of a normal longitudinal combined discharge when DC and RF voltages are applied to the same electrodes. Previously it was shown that longitudinal combined discharge can burn in three possible modes. In this work it is shown that when we apply the RF voltage to the combined discharge burning in the third mode (DC discharge perturbed by the RF electric field) there is almost no influence on the DC current magnitude and the area occupied by the discharge spot

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... t the "cathode". However after transition to the second mode with the RF voltage growth, a fast increase of the DC current and broadening of the discharge spot is observed. It is shown that in the normal combined discharge as well as in the DC discharge, a transition pressure range exists, where j/p 2 is not the constant value but decreases with the discharge current increase. The radial profiles of the discharge current density in normal and abnormal modes of longitudinal combined discharge and the axial profiles of the discharge were experimentally investigated, and modeling of the combined discharge using program Oopic Pro was made. It is shown that both normal and abnormal combined discharges can burn in three modes, and have two peaks of the glow intensity near the "anode" which are formed in the second mode.