Speaker
Remi Capdessus
Description
See the full Abstract at http://ocs.ciemat.es/EPS2018ABS/pdf/P4.2002.pdf
Relativistic Doppler-boosted γ-rays in High Fields
R. Capdessus1 M. King1, D. Del Sorbo2, M. J. Duf1, C. P. Ridgers2 and P. McKenna1
1.
Department of Physics SUPA, University of Strathclyde, Glasgow G4 0NG, United Kingdom
2.
York Plasma Institute, Department of Physics
The relativistic Doppler efect is one of the most famous implications of the principles of special
relativity and is intrinsic to moving radiation sources, relativistic optics and many astrophysical
phenomena. It occurs in the case of a plasma sail accelerated to relativistic velocities by an external
driver, such as an ultra-intense laser pulse. The construction of several international multi-petawatt
laser facilities (e.g. APOLLON in France, ELI-NP in Bucharest and ELI-Beamlines in Prague) are
anticipated to produce field intensities on the order of 10 23-1024 W/cm2, where the gamma ray
emission and pair production will be copious [1]. In such interaction regimes involving ultra-strong
electromagnetic fields, the ions can no longer be considered as “background plasma particles” since
the quiver electron energy can be comparable with the ion rest mass [2]. Through an analytical
model and 2D QED-PIC simulations, we show that the relativistic Doppler efect on the high energy
synchrotron photon emission (∼ 10 MeV), strongly depends on the intrinsic properties of the
plasma (charge state and ion mass) and the transverse extent of the driver [3]. When the moving
plasma becomes relativistically transparent to the driver, we show that the γ-ray emission is
Doppler-boosted and the angular emission decreases; optimal for the highest charge-to-mass ratio
ion species (i.e. a hydrogen plasma). This new fundamental insight into the generation of γ -ray
sources in various extreme conditions will be significant for experiments on multi-petawatt laser
facilities.
[1] A. Di Piazza, C. Müller, K. Z. Hatsagortsyan, and C. H. Keitel Mod. Rev. Phys. 84 (2012).
[2] R. Capdessus, E. d’Humieres, and V. T. Tikhonchuk Phys. Rev. Lett. 110 , 215003 (2013).
[3] R. Capdessus, M. King, D. Del Sorbo, M. J. Duf, C. P. Ridgers, and P. Mckenna, submitted to Scientific Reports.
