Multi-messenger dynamic imaging of laser-driven shocks in water using a plasma wakefield accelerator

Understanding dense fuel hydrodynamics is critical for predicting burning plasma behavior in laser-driven inertial confinement fusion. Traditional diagnostic sources face many limitations in brightness, spatio-temporal resolution, and their ability to capture kinetic effects and electromagnetic fields influencing interaction dynamics. We present a dual-probe, multi-messenger laser wakefield accelerator system, combining ultrafast X-rays and relativistic electron beams at 1~Hz, to interrogate a free-flowing water target in vacuum heated by an intense 200~ps laser pulse. This unique scheme enables high-repetition-rate tracking of the interaction evolution utilizing both particle types. Betatron X-rays revealed a cylindrically symmetric shock compression morphology assisted by low-density vapor, resembling foam-layer-assisted fusion targets. The synchronized electron beam detected time-evolving electromagnetic fields, uncovering charge separation effects and ion species differentiation during plasma expansion – phenomena not captured by photons or standard hydrodynamic simulations. This multi-messenger approach highlights the need for hybrid physics models that integrate the detailed insights from both probes, spanning kinetic to hydrodynamic effects, to accurately predict fusion-relevant plasma dynamics from femtosecond to nanosecond timescales.