Laser-driven ion acceleration with hollow laser beams

Abstract

The laser-driven acceleration of protons from thin foils irradiated by hollow high-intensity laser beams in the regime of target normal sheath acceleration (TNSA) is reported for the first time. The use of hollow beams aims at reducing the initial emission solid angle of the TNSA source, due to a flattening of the electron sheath at the target rear side. The experiments were conducted at the PHELIX laser facility at the GSI Helmholtzzentrum für Schwerionenforschung GmbH with laser intensities in the range from 1018 W cm−2 to 1020 W cm−2. We observed an average reduction of the half opening angle by (3.07±0.42)° or (13.2±2.0)% when the targets have a thickness between 12 μm and 14 μm. In addition, the highest proton energies were achieved with the hollow laser beam in comparison to the typical Gaussian focal spot.

High Orbital Angular Momentum Harmonic Generation

“…Raman backscattering has been investigated in the frame of onedimensional physical models [23,24], focusing on energy flows between the intervening waves. As an application, we recently showed that Raman backscattering can amplify seed pulses with a single OAM level to the required intensities to explore relativistic laser-plasma interactions [21,[25][26][27]]-by using a counter-propagating long pump laser that also contains a single OAM mode [28]. Here we demonstrate that three-wave interactions can also be used to manipulate, with an unprecedented degree of controllability, the three-dimensional spatial-temporal laser pulse structure.…”

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).…”

Interaction of annular-focused laser beams with solid targets

“…Another application of the annular laser pulses is the laserdriven acceleration of protons from thin foils irradiated by hollow high-intensity laser beams in the regime of target normal sheath acceleration (TNSA) (Brabetz et al, 2015). In this case, the use of annular beams aims at reducing the initial emission solid angle of the TNSA source (Brambrink et al, 2006;Yu et al, 2013), due to a flattening of the electron sheath at the target rear side.…”

“…In this case, the use of annular beams aims at reducing the initial emission solid angle of the TNSA source (Brambrink et al, 2006;Yu et al, 2013), due to a flattening of the electron sheath at the target rear side.…”