Ultrafast electron radiography for the evolution of electric field generated from a tungsten wire by intense laser irradiation

In this work, the transient electric field generated by a tungsten wire with a 100 mu m diameter after the irradiation by a $ 6.4\times 10<^>{13} $ 6.4x1013 W/cm $ <^>2 $ 2 laser pulse has been investigated utilizing ultrafast electron radiography with high spatial resolution. To address the complexity of image processing, an automated program has been developed to enable rapid and precise extraction of probe electron beamlets from snapshots. Derived from the program, the deflection evolution of probe electron beamlets is analyzed. The evolution curves of the local probe electron beamlets on either side of the tungsten wire exhibit significant asymmetry, with their average curve indicating a repulsive effect persisting for approximately 200 ps. By the quantity of deflection of the probe electrons, the average electric field strength in the two directions is calculated to be $ \bar {E_x}=1.3\times 10<^>4 $ Ex<overline>=1.3x104 V/m and $ \bar {E_y}=1.2\times 10<^>4 $ Ey<overline>=1.2x104 V/m, respectively. These findings provide experimental evidences that will inform future studies on the transient electric fields incuded in the interaction of the laser with metallic wire.