Recovery of hydrogen plasma at the sub-nanosecond timescale in a plasma-wakefield accelerator

TL;DR

This paper demonstrates the rapid recovery of hydrogen plasma at sub-nanosecond timescales using a pump-probe setup, advancing plasma wakefield accelerator technology towards high-repetition-rate operation.

Contribution

It provides the first experimental evidence of hydrogen plasma recovery at sub-nanosecond timescales, supported by numerical simulations, crucial for high-repetition-rate plasma accelerators.

Findings

Large plasma densities recover within 0.7 ns after pump injection.

Lower densities form dense plasma channels affecting probe dynamics at >13 ns.

Experimental results are supported by numerical simulations.

Abstract

Plasma wakefield acceleration revolutionized the field of particle accelerators by generating gigavolt-per-centimeter fields. To compete with conventional radio-frequency (RF) accelerators, plasma technology must demonstrate operation at high repetition rates, with a recent research showing feasibility at megahertz levels using an Argon source that recovered after about 60 ns. Here we report about a proof-of-principle experiment that demonstrates the recovery of a Hydrogen plasma at the sub-nanosecond timescale. The result is obtained with a pump-and-probe setup and has been characterized for a wide range of plasma densities. We observed that large plasma densities reestablish their initial state soon after the injection of the pump beam (< 0.7 ns). Conversely, at lower densities we observe the formation of a local dense plasma channel affecting the probe beam dynamics even at long delay times (> 13 ns). The results are supported with numerical simulations and represent a step forward for the next-generation of compact high-repetition rate accelerators.