Initial stages of pulsed discharge in saline solutions in a vicinity of threshold voltages

Abstract

The data on investigation of the pulsed discharge in solution 30 g of NaCl per liter of distilled water are presented. The interelectrode gap consists of the active pin electrode and the return plane electrode. The voltage pulse of positive polarity forms by means of the electric circuit where the capacitor bank of 40 µF with an initial voltage V0 up to 1500 V is discharged via the gap. In a range of initial voltages V0 = (550–1100) V the vapor cavities in a form of the microbubbles are generated near the active electrode and at the electrode surface. The microbubbles are able to merge with each other thus forming the macrobubbles and the vapor layers, which shield the active electrode from the current passage. The process of vapor cavity generation and the effect of shielding are discussed in detail. The discharge at the vapor layer appears at the critical voltage V0 = 1100 V. The principal prerequisite for discharge arising is that the electrode has to be completely shielded by the vapor layer and the voltage at the layer to the instant of discharge initiation has to be at least at a level of 500 V. However, when the voltage at the gap exceeds the critical value, the condition of complete shielding is not obligatory.

Plasma Scalpels: Devices, Diagnostics, and Applications

“…A typical two-electrode discharge device in normal saline is shown in Figure 1 b [ 8 ], where the anode is a set of three metal-alloy wire electrodes mounted on the scalpel head [ 9 , 10 , 11 ], and the exposed stainless-steel tube is the return ground electrode. The anode is embedded in a ceramic spacer to ensure separation from the return ground electrode.…”

“…The two-electrode plasma scalpel is discharged by immersing the anode and ground electrodes in a fluid with a low dielectric constant ( Figure 1 b) [ 15 ]. The liquid required during the plasma scalpel treatment is usually isotonic saline [ 11 , 16 , 17 ], containing 0.9% NaCl dissolved in water and other small amounts of buffer salts to maintain the optimum acid-base balance. Isotonic saline is conductive due to dissolved ions.…”