Characterizing Magnetic and Electric Fields from Laser-Driven Coils Using Axial Proton Probing*

Developing the capability to generate 100+ Tesla (T) magnetic fields to magnetize laser-produced plasmas has been one of main goals of recent high-energy-density–physics research. Recent experiments seem to indicate that laser-driven currents flowing within millimeter-size coils can potentially produce 100 T+ level seed fields. However, in many experiments there have been large discrepancies between magnetic-field values claimed across different diagnostics. The group at LLE has developed an experimental platform to verify and distinguish electric and magnetic fields by using axial proton radiography. Synthetic radiographs were generated by explicitly solving for magnetic and electric fields given a set of defined charge and current distributions. These radiographs were compared for multiple proton probe energies and measured a 60-T magnetic field along with a substantial electric field at the center of the coil. Field measurements were taken for both single- and double-plate “capacitor” style coil targets.