Diffusion of Electromagnetic Field into the Core of Inductor at Induction Accelerator of Electrons

Abstract

Summary form only given. High energy electronic accelerator based on the inductive principle of particle interaction with accelerating field have used mostly the short pulses of voltage applied to each stage of accelerator. The typical width of pulse is concluded in the range 50... 250 nanoseconds. Such duration of electromagnetic process leads to necessity to use the magnetic material for the core manufacturing with intrinsic low specific energy losses at high speed of core magnetization reversal, measured as ratio of magnetic induction swing to duration of this process, usually in Tesla per microsecond (T/mus). The amorphous materials as Metglas of several kinds produced by Honeywell company is most suitable for this application (Smith and Barberi, 1985). These materials have the rectangle remagnetization curve, high magnetic permeability and valid level of energy losses at the remagnetization speed up to 3.0 T/mus. The core of inductor is prepared always in the form of ring by winding of amorphous magnetic material on the base of polymer strip. Resulting multi-layer structure of core (flicker of magnetic and non-magnetic films) has stipulated the anisotropic magnetic properties of core and has the strong influence on the speed of magnetic field diffusion into the cross section of core. Analysis of this question shows that dimensions of core cross section must be matched with a speed of the field diffusion to be sure that full cross section is filled by magnetic flux in the process of remagnetization. In the work proposed the value of the field diffusion speed has been calculated for both direction (along the magnetic layers and across them) and has been loaded into simulating program "Quick Field" which gives a possibility to take into account the anisotropv of core in the transient process of the field penetration. Longitudinal and transversal speed of the field diffusion is the function of electrical and magnetic properties of Metglas layer and wafer layer as well as function of their thickness" ratio. The procedure developed for the initial data of core preparing and following simulation of the field penetration process into the core in the natural time scale enables to resolve any practical problem of the inductor core design respectively to the real geometrical characteristics of accelerator elements and to the real time parameters of the energy supply pulse.