Charged particle deflectometry of strong magnetic field generation driven by intense laser-solid interactions*

In experiments performed at the OMEGA EP laser facility, proton deflectometry was used to capture the spatial and temporal evolution of magnetic fields generated during both moderate (I_L ~ 10¹⁴ Wcm^-2) and high (I_L > 10¹⁸ Wcm^-2) intensity laser-solid interactions.  The strong fields and short timescales associated with high intensity interactions pose a significant challenge to proton image interpretation methods, especially as large deflections result in proton trajectory crossing and caustic formation.  Consequently, we investigate the application of relativistic electron beams from laser-wakefield accelerators for ultrafast deflectometry measurements of large amplitude laser-driven magnetic fields.  In addition to attractive imaging properties (ultrashort bunch duration and low emittance), laser-wakefield sources readily scale to high-repetition rate experiments.  A conceptual design for relativistic electron deflectometry experiments will be presented, along with considerations of realistic beam parameters, such as energy spread and finite emittance, and incorporating magnetic beam optics.