Pulse generator for a scalable discharge plasma source for the AWAKE experiment

Pulsed electrical discharges can generate plasmas suitable for wakefield particle acceleration experiments. This thesis describes the development and design of a semiconductor-based high-voltage and high current pulse generator topology for a plasma source for the Advanced WAKEfield Experiment (AWAKE). A plasma source for AWAKE depends upon unique parameters regarding the length (typically 10 m), plasma electron density (∼ 7 × 1014 $cm^{−3}$ ), reproducibility, scalability, and density uniformity (< 0.25% over 10 m). Plasma discharges present unique challenges for power electronic systems due to the highly non-linear plasma dynamic behaviour. To operate under the required length, reproducibility and density values, the pulse generator uses two voltage pulses, the first for the processes of ignition, using a fast-rising high-voltage pulse to generate the plasma with minimum jitter; and the second for heating, taking advantage of the lower impedance to boost the current and consequently the plasma density with high reproducibility. Furthermore, to meet the scalability objectives multiple neighbouring synchronised plasma discharges can be produced using high-frequency coupled inductors to equalise the current amplitudes. This thesis describes the double pulse generator design, component selection, the development of the coupled inductors balancing modules, PSpice simulations of the pulse generator using a suitable plasma model, and the experimental results of the discharge plasma source double pulse generator. Additionally, this thesis provides an account of the plasma source operation in the AWAKE experiment, reporting its first use in its intended application.