Speaker
Bertrand Martinez
Description
See the full Abstract at http://ocs.ciemat.es/EPS2018ABS/pdf/P4.2016.pdf
Synchrotron emission from nanowire-array targets irradiated by
ultraintense laser pulses
B. Martinez1,2 , E. d’Humières2 , L. Gremillet1
1 CEA, DAM, DIF, F-91297 Arpajon, France
2 CELIA, UMR 5107, Université de Bordeaux-CNRS-CEA, 33405 Talence, France
Forthcoming multi-petawatt lasers will enable scientists to access a new regime of laser-
plasma interactions where collective plasma processes are intertwined with radiative and quan-
tum electrodynamics effects, offering exciting prospects for fundamental and applied research
[1, 2, 3, 4]. One underlying mechanism common to all these applications is the copious gen-
eration of hard x-ray or γ-ray photons through synchrotron emission–equivalent to nonlinear
inverse Compton scattering in the strong-field regime.
Here we present the results of two-dimensional particle-in-cell simulations of the synchrotron
emission from carbon nanowire arrays irradiated by femtosecond laser pulses of intensities
I = 1021 − 1023 Wcm−2 . The realization of intense laser-driven synchrotron sources is but the
latest application of nanowire arrays, whose capability in strongly enhancing the laser energy
absorption and hot-electron generation is now well established and exploited [5, 6]. Through
an extensive parametric scan on the laser-target parameters, we identify and characterize sev-
eral dominant radiation mechanisms, mainly depending on the transparency or opacity of the
plasma produced by the laser-driven wire expansion, and on the quasistatic fields self-induced
around the wires. At I = 1022 Wcm−2 , the emission of high-energy (> 10 keV) photons attains a
maximum energy conversion efficiency of ∼ 10% for ∼ 30 − 50 nm wire widths and 1 µm inter-
spacing. While this maximum radiation yield does not exceed that achieved in uniform plasma
of same average (sub-solid) density, we show that nanowire arrays provide efficient radiation
sources over a broader parameter range. Finally, we demonstrate that the radiation efficiency
can be further boosted by adding a plasma mirror at the backside of the nanowire array.
References
[1] A. Di Piazza, C. Müller, K. Z. Hatsagortsyan, and C. H. Keitel, Rev. Mod. Phys. 84, 1177 (2012).
[2] C. P. Ridgers et al., Phys. Rev. Lett. 108, 165006 (2012).
[3] L. L. Ji et al., Phys. Rev. Lett. 112, 145003 (2014).
[4] M. Lobet et al., Phys. Rev. Lett. 115, 215003 (2015).
[5] L. Cao et al., Phys. Plasmas 17, 043103 (2010).
[6] M. A. Purvis et al., Nature Photon. 7, 796 (2013).
