Biot-Savart for bifurcation, BSBIF

Abstract

To this date, most (perhaps all) computer simulations and models (including Care'n Co.'s code CAGEN [1]) that are capable of being used to predict the behavior of helical flux compression generators (HFCG) approximate both the helicity of the windings and the bifurcations. The spiral nature of the windings is approximated with loops that lie in a plane perpendicular to the axis of the HFCG. Perhaps the most notable approximation is the assumption that the currents in each of the bifurcate legs are equal. There have been a few experiments that have measured the currents in each “parallel” winding separately, and those measurements have shown that the currents are not equal (none of these experiments have been published). The concern, then, is that the electrical fields within the HFCG will not be represented accurately by those approximations. To examine these short falls, The Care'n LLC has developed a HFCG modeling code that treats the windings in their actual spiral and bifurcated form and, further, allows the currents in each wire to be computed self consistently. This code is called (for the time being) BSBIF standing for Biot-Savart BIFurcation. The details of BSBIF, its implementation, running speeds, and comparisons to CAGEN are presented. No bifurcation issues regarding internal electrical breakdown have been found.