The thermodynamic properties of erosion plasma produced by diaphragm discharge in jets in vacuum

An experimental study is made of the thermodynamic properties of plasma flowing from the orifice of a plasma-forming diaphragm as a function of the size of the orifice of the diaphragm made of textolite $(\mathrm{C}_{37}\mathrm{H}_{47}\mathrm{O}_{16})$ under conditions of a diaphragm discharge in jets in vacuum ($P_{\text{init}}=13.3-1.3$ Pa). The data are obtained for a fixed energy supply in a wide range of variation of the diaphragm opening size, namely, the diaphragm thickness $l_0=2.0–20.0$ mm and the diameter of the orifice $2r_0=2.0–12.0$ mm. The increase of pressure and temperature in the jet is shown to slow down with an increase of the thickness $l_0$ with the constant diameter of the diaphragm orifice $2r_0$.