Physical-Topological Modeling of Electronic Devices with Induction Heating of Particle Emitters

Abstract

The general principles of physical and topological modeling and construction of algorithms for calculations of a wide range of electronic devices with induction heating of functional elements up to temperatures at which thermoelectronic emission and/or evaporation of the working substance in the atomized state are considered. The direction of physical-topological modeling was chosen due to the possibility of detailed analysis, based on the primary principles for related physical processes in devices, taking into account the impact of physical properties of functional elements and their design and topological (i.e. geometric) parameters. Thus, the results are obtained by solving a system of fundamental equations, which usually include Newton's and Maxwell's equations, the conservation laws of particles, charge, energy and momentum, as well as material properties, boundary and initial conditions. The set of equations is determined by the number of processes that significantly affect the operation of devices. The construction of the device model is based on the consistent hierarchy of elementary physical processes with the sequential transfer of the results of calculations for lower-level models to higher-level models in the form of initial conditions. The original mathematical models of elementary processes are represented by systems of integral-differential equations with partial derivatives in continuous space and continuous time and belong to the class of distributed mathematical models. Methods for solving the system of equations are considered. On the example of a vacuum metal evaporator with induction heating for thermovacuum coating deposition, the procedure of decomposition of the general physical process in the evaporator with a concentrator as a step-down transformer is given and the hierarchy of elementary processes is clarified. Typical initial and boundary conditions for calculating related physical processes are determined. The available application computer soft packages for the calculation of physical and topological models of various induction devices are considered. In the final part of the article it is considered the structure and structure of physical-topological models of devices with induction heating of particle emitters: i) the thermoionic metal evaporator with ionization of vapor by electrons emitted by a thermocathode from an alloy with low electron output, the cathode is made in the form of an insert on the upper end of the crucible, and ii) the X-ray tube with an inductively heated thermoelectron cathode. Calculation results of the electromagnetic field and current distribution, heat exchange in vapor and electron emitters and their emission fluxes, as well as the trajectories of emitted electrons are presented. Analysis of electron trajectories allowed to optimize the topology and design of these devices.