Vortex Electron Flows in Magnetically Insulated Transmission Lines of Megaampere Pulse Generators with Low-Impedance Loads: Numerical Simulation

Numerical experiment using KARAT electromagnetic PiC code demonstrated а vortex structure of electron flows arising in magnetically insulated lines with an inductive load, fed with sub-microsecond megaampere current pulse, under condition of space charge limited electron emission from the line conductors. It was found that no significant energy loss is associated with the electron vortices. Additional space charge-limited emission of positive heavy ions does not make the losses critical but causes degradation of the vortex structure as the ions accumulate. The vortices can reach the separating insulator, producing a threat to its electrical strength. Closing a shortening switch installed at the entrance of the vacuum segment of the line provides effective interception of the electron flows. Intense sub-gigahertz voltage oscillations have been observed in the nonuniform lines, apparently excited by the moving electron vortices.