Space structure of RF capacitive discharges

Summary form only given. The space structure of RF capacitive discharges along the direction of a current is well known. The most important features of it are: 1) RF capacitive discharge has a sheath structure along the direction of the current, including near electrode space charge sheaths and plasma column. 2) The sheaths can have different physical nature, depending on value of U/sub s/-RF voltage upon them. The sheaths cannot be self-sustained at U/sub s/U/sub BR/ (high-current mode). U/sub BR/-RF is the voltage upon the sheaths, at which their breakdown with the help of secondary emission electrons occurs. In this work an interesting and practically not investigated phenomenon, when both of the above mentioned modes of the discharge exist simultaneously in one interelectrode gap, is considered. Besides academic interest, this phenomenon is significant for practical applications, in which uniformity of the discharge along the surface of extended electrodes is important (for example, in gas lasers with transverse RF excitation, in plasma technology, etc.). The experiments were carried out in atomic and molecular gases at pressures from 0.1 up to 300 Torr. The area of electrodes reached the value 10/sup 3/ cm/sup 2/, and the size of an interelectrode gap was up to 10 cm. RF sources of power up to 6 kW on frequencies from 1 to 100 MHz were used.