Proton radiography of magnetic fields in a laser-produced plasma

Magnetic and electric fields generated by the interaction of long-pulse laser beams with plasmas relevant to inertial confinement fusion have been measured. A proton beam generated by the interaction of an ultraintense laser with a thin metallic foil is used to probe laser-produced fields. The proton beam is temporally short (on the order of a picosecond at the source position) and highly laminar, and hence equivalent to a virtual point source which makes it an ideal source for point projection radiography. We have investigated, using face-on and side-on radiography, fields due to the non-collinearity of temperature and density gradients at laser intensities around 5 × 10¹³ W/cm².