Enhanced Relativistic-Electron-Beam Energy Loss in Warm Dense Aluminum

Electron acceleration at grazing incidence of a subpicosecond intense laser pulse onto a plane solid target

“…In this paper, the generation of hot electrons at grazing incidence of a subpicosecond intense laser pulse onto a plane solid target is analyzed for the parameters of the petawatt high-energy laser for heavy ion experiments (PHELIX) (Bagnoud et al, 2010;Wagner et al, 2014a) using three-dimensional (3D) particle-in-cell (PIC) modeling (Pukhov, 1999) and a wide-range hydro modeling (Povarnitsyn et al, 2012a) of the preplasma expansion under the action of the laser prepulse. Elaboration of wide-range models of the laser-matter interaction is necessary for planning and interpretation of experiments carried out in view of different applications aimed for the development of secondary sources of high energy particles and hard radiation (Morace et al, 2014;Brabetz et al, 2015;Rusby et al, 2015;Vaisseau et al, 2015). Surface acceleration and transport of energetic electrons in intense laser-matter interactions at the grazing incidence were investigated experimentally for femtosecond laser pulses of hundreds mJ energy in (Wang et al, 2013;Mao et al, 2015) and for hundred joule subpicosecond laser pulses of the laser system PHELIX in paper (Gray et al, 2011).…”

Collimated Propagation of Fast Electron Beams Accelerated by High-Contrast Laser Pulses in Highly Resistive Shocked Carbon

“…The use of a hollow cone re-entrant into the capsule provides a clear pathway for the ignitor laser till the cone tip [10,11], moving the REB-source as close as 100 µm from the high-density core [12]. Yet, the challenge persists of confining the REB propagation within a small radius, while limiting both resistive and collisional energy losses over the compressed plasma [13][14][15] as well as REB-source perturbations either by cone-tip ablation by the laser intensity-pedestal [16][17][18] or by tip disruption due to the high-pressure of the asymmetrically imploded plasma [19].…”

“…1 b) shows sample data as a function of ∆t, from ∆t = 0 ns (REB injection into an unperturbed solid-cold vitreous-C target), up to ∆t = 4 ns (1 ns after shock-breakout time at the inner cone-tip surface; REB generation in an expanding plasma filling the cone volume). The use of the LP laser also for the ∆t = 0 -case allowed the formation of a long CH ablation-plasma that prevented fast electrons from recirculating after their first transit through the Cu layers [13,35]. The simulated density and temperature maps at the corresponding delays are presented on Fig.…”

“…For ∆t = 2.5 ns, the rear side tracer is being pushed towards the cone tip by the compression shock, as seen on the hydro simulation. The tracer fluorescence yield is higher with respect to the ∆t = 0 image, in relation to a reduction of the fast electrons energy-loss due to the resistive effect (collisional losses are kept the same for samples of identical areal mass) [13]. An important feature is that the tracer emission size is of the same order as that from the cone tip, consistent with its 50 µm-diameter, despite the several tens of microns propagation distances, as it is shown on Fig.…”

Measurement of reflectivity of spherically bent crystals using Kα signal from hot electrons produced by laser-matter interaction

“…2,3 In particular, in the Fast Ignition (FI) approach to ICF, a current of relativistic electrons generated by an intense laser pulse (>10 19 W/cm 2 ) should propagate to the compressed core generating a hot spot. 4 The conversion efficiency of laser energy into fast electrons, 5 the propagation in warm dense matter, 6,7 and the divergence of the beam are crucial for FI, and they have to be carefully characterized. Hot electrons generated by parametric instabilities (stimulated Raman scattering and two plasmon decay) and resonant absorption could also have a significant role in Shock Ignition 8 (SI).…”