 The vortices approached each other, collided, repelled each other, and finally came to rest.At that time the compression coils produced a 3.5 T field with a quarter-cycle rise time of 10 μs.The compressed rings retained their structure for 5 μs, with a density of 2 x 1017 cm−3, an ion temperature of 5 keV, an electron temperature of 300 eV.