Experimental study on laser-driven electron collimation along wire targets

We present an experimental study of electron collimation triggered by an ∼1 × 10¹⁸ W/cm² laser pulse irradiated onto wire-like targets. The collimation effect is observed to vary with the laser intensity and target shape. From the resulting electron angular distributions obtained under different experimental conditions, we deduce that the collimated electron charge grows in proportion with the -1/2 power of wire diameters and the square of pulse energies. Numerical simulations are conducted to study the electron behavior's dependence on the transient field and experimental conditions and are found to reproduce the experimental features.