Experimental evidence of electric inhibition in fast electron penetration and of electric-field-limited fast electron transport in dense matter

Abstract

Fast electron generation and propagation were studied in the interaction of a green laser with solids. The experiment, carried out with the LULI TW laser (350 fs, 15 J), used K(alpha) emission from buried fluorescent layers to measure electron transport. Results for conductors (Al) and insulators (plastic) are compared with simulations: in plastic, inhibition in the propagation of fast electrons is observed, due to electric fields which become the dominant factor in electron transport.

Short Pulse Laser Absorption and Energy Partition at Relativistic Laser Intensities

“…We measure the hot-electron relexation time (defined as the FWHM of I Kα ) to be 15.9, 13.2, and 12.3 ps, for the laser intensities 10 19 , 10 18 , and 10 17 W/cm 2 , respectively. Note that the K α emission durations in our experiment are significantly larger than those measured previously 43,23 . This is due to (i) our hot, electron temperatures are at least one order of magnitude larger; (ii) as a consequence, the hot electron range here is many times the target thickness so that multiple interaction and K α generation can occur with parts of the target that are transparent for K α radiation.…”

High-energy ion generation in interaction. of short laser pulse with high-density plasma

“…The physical picture of this transformation arising in the bulk of the target is still incomplete. Note that [28] sheds some light on the latter issue, demonstrating a four times difference in the penetration depth of fast electrons in metals and insulators due to the effect of a self-consistent electric field, which pulls electrons back.…”

Short-pulse laser-driven x-ray radiography

“…a large number of energetic electrons is generated [4,5] , which propagates into the sample. These electrons will either emit continuous radiation via the Bremsstrahlung process or create K-shell vacancies via impact ionization, which leads to characteristic line emission (K α and K β ).…”