Laser-driven relativistic electron beam interaction with solid dielectric

Abstract

The multi-frames shadowgraphy, interferometry and polarimetry diagnostics with sub-ps time resolution were used for an investigation of ionization wave dynamics inside a glass target induced by laser-driven relativistic electron beam. Experiments were done using the 50 TW Leopard laser at the UNR. For a laser flux of ∼2×1018W/cm2 a hemispherical ionization wave propagates at c/3. The maximum of the electron density inside the glass target is ∼2×1019cm−3. Magnetic and electric fields are less than ∼15 kG and ∼1 MV/cm, respectively. The electron temperature has a maximum of ∼0.5 eV. 2D interference phase shift shows the “fountain effect” of electron beam. The very low ionization inside glass target ∼0.1% suggests a fast recombination at the sub-ps time scale. 2D PIC-simulations demonstrate radial spreading of fast electrons by self-consistent electrostatic fields.