Double pulse generator for AWAKE scalable discharge plasma source

Abstract High-voltage pulsed discharges can produce suitable plasmas for wakefield acceleration experiments, such as the Advanced Wakefield Experiment (AWAKE) at CERN. Using two successive voltage pulses, the first for plasma ignition (~20 kV) followed by a second pulse (~500 A) for plasma heating, it is possible to effectively obtain a highly reproducible plasma lasting tens of microseconds, by taking advantage of the low impedance state created by the first pulse. A discharge plasma source (DPS), based on this principle was installed in the AWAKE experiment producing over 21 thousand plasma discharges and was tested with a double-plasma set-up (3.5 + 6.5 m plasma length) using two pulse generators and a shared cathode. It was operated as well with different single plasma loads: three different gases (xenon, argon, and helium) and three different plasma lengths (3.5, 6.5 and 10 m). The DPS performed with ~20 ns jitter and ~1% current variability. Current balancing between two plasmas was possible even with asymmetric plasma lengths.