Optimizing the Coupling of Vacuum Power Flow from a Versatile Induction Voltage Adder to a Range of Diodes

Reference 1 in this conference described an induction voltage adder (IVA) based on gas-switched pulse forming lines (pfl). The pfls and induction cells can be configured in different architectures to drive a variety of radiographic electron diodes with different characteristics. The impedances range from that of the paraxial diode with an impedance of hundreds of ohms at voltages ges 14 MV to various types of pinched diodes in the 40-ohm impedance range at les 10 MV. Efficient coupling of an IVA to diodes with such diverse impedances requires not only the reconfiguration of the pfls and induction cells but also re- optimizing of the vacuum power flow to the diode. The useful power available to the radiographic diode can be maximized by the correct choice of the cell/pfl impedances (IVA architecture) and the impedance of the self-magnetically insulated transmission line for a given characteristic radiographic diode impedance and voltage and current dependence of the radiated energy from the diode. This optimization utilizes re-trapping of the vacuum electrons and can include a non-emitting region near the diode. Using parapotential [2] and re-trapping theory [3], along with particle-in-cell simulations (LSP [4]) we summarize how these techniques are used to provide the versatility needed by the AWE HRF IVA that is being designed and prototyped by Titan Pulsed Sciences Division.