TRIFL: a design tool for modeling complex magnetically insulated transmission line geometries

Abstract

Summary form only given. Vacuum power flow in modern high-power pulsed accelerator transmission lines requires field stresses at the conductors that are so high that negative surfaces become space-charge-limited electron emitters. The performance of these lines can be calculated using two- and three- dimensional, time-dependent, particle-in-cell electromagnetic codes, such as TWOQUICK and QUICKSILVER. Extensive design of complex systems using these simulation codes would be extremely expensive and, perhaps, impossible for many of the new pulsed power systems being planned. Generalized modeling of power flow using the concept of flow impedance has demonstrated that at high voltages (>0.511 MV), the electrons dynamics can be modeled very well using pressure balance. An analytic model has been developed which includes the effects of these electrons and accurately predicts the behavior of magnetically insulated transmission lines. The model uses flow impedance parameters with an expanded set of telegrapher's equations to calculate radial currents in the transmission lines, this model has been implemented in a code, TRIFL (triple-equation-flow model), on workstations and PCs and allows us to do detailed designed studies on systems far too complex for similar treatment using a PIC code. TRIFL is run from IDL and has a graphical user interface. The driver for the transmission line can be analytic or tabular. Loads include a time-dependent impedance, a constant perveance diode, and an imploding plasma load (using a foil load model).