Theoretical studies of vacuum arc processes carried out in the laboratory allowed to develop a physical and mathematical model of a plasma jet of a high-current vacuum arc in an external axial magnetic field. Based on this model, a computer program IonGun 1.1, which calculates the electrodynamic and energy characteristics of the plasma of a high-current vacuum arc in an external magnetic field. At the input of the program, the geometric parameters of the electrode system, the characteristics of the electrode materials, the arc current and the external magnetic field are set. The results of the calculations are spatial distributions of the main physical characteristics of the arc discharge, such as: current density, plasma concentration, average plasma charge and its charge components, electron and ion temperatures, ion velocity, etc.. The program is written in FORTRAN-95 language, optimized for calculations on all modern processors (including Pentium 4 and AMD Athlon) and works in Microsoft Windows 95/98/2000/XP operating system with user-friendly interface (see Fig. 1). More detailed information about the physical and mathematical model, applied numerical methods and description of the program can be downloaded here.
Fig. 1. The user interface of IonGun 1.1 and examples of graphical representation of the calculated spatial distributions of plasma parameters of a vacuum diode with magnetic insulation. |
The proposed program can be used in the development and creation of high-current electrophysical devices operating on the basis of a vacuum arc; the choice of the most optimal modes of operation of the existing arc ion sources and current switches.
Using the IonGun 1.1 program, a complex of physical processes responsible for the formation of a collectivized jet of a high-current vacuum arc is studied. It is shown that the average charge of plasma ions increases with an increase in the external magnetic field and the total arc current. With a field/current ratio of 10 Gauss/Ampere and a current of 1 kA, a twofold increase in the average ion charge for the titanium cathode was obtained. Moreover, in this case, the "freezing" of the ion composition taking place in a low-current vacuum arc does not occur. The average charge of arc plasma ions continuously increases along the entire discharge gap. The values of the average ion charge obtained by the computational experiment are in good agreement with the available experimental data.