Generation and characterization of warm dense matter isochorically heated by laser-induced relativistic electrons in a wire target

Abstract

We studied the interaction of a high-intensity laser with mass-limited Ti-wires. The laser was focused up to 7 × 10 20 W/cm 2 , with contrast of 10 −10 to produce relativistic electrons. High-spatial-resolution X-ray spectroscopy was used to measure isochoric heating induced by hot electrons propagating along the wire up to 1 mm depth. For the first time it was possible to distinguish surface target regions heated by mixed plasma mechanisms from those heated only by the hot electrons that generate warm dense matter with temperatures up to 50 eV. Our results are compared to simulations that highlight both the role of electron confinement inside the wire and the importance of resistive stopping powers in warm dense matter.

Diagnosis of warm dense conditions in foil targets heated by intense femtosecond laser pulses using Kα imaging spectroscopy

“…The targets were free-standing titanium foils of 1-10 μm in thickness. The target front surface (laser irradiated side) was coated with 100 nm of aluminum to prevent the direct interaction between the intense laser and bulk titanium and the generation of low-density hot Ti plasma emitting Kα radiation [20,22,25]. After each laser shot, the target was translated to the fresh surface.…”

Propagation-based imaging phase-contrast enhanced imaging setup for single shot acquisition using laser-generated X-ray sources

“…A simpler approach could be the laser-irradiation of solid targets, which produces X-ray radiation. Using short and intense laser pulses it is possible to transfer a significant fraction of laser energy to a suprathermal electron population (16). The propagation of these fast electron inside a solid target produces a strong continuum broadband emission which can be used as a backlighter.…”

Targets for high repetition rate laser facilities: needs, challenges and perspectives

“…WDM states have also been recently studied by irradiating the upper base of cylindrical Ti targets ( diameter and length) [36] . This configuration separates regions heated by plasma absorption mechanisms from those heated by hot-electron propagation only (up to 1 mm from the laser–target interaction region, reaching temperatures up to 50 eV).…”