• J.L. Martins, R.A. Fonseca, S.F. Martins, L.O. Silva
  Instituto Superior Tecnico, Lisbon
• C. Joshi, W.B. Mori
  UCLA, Los Angeles, California

Funding: F.C.Gulbenkian, F.C.T. [SFRH/BD/35749/2007, SFRH/BD/39523/2007, PTDC/FIS/66823/2006 (Portugal)], and European Community (project EuroLeap, contract #028514)

It is now accepted that self-trapped electrons in a laser wakefield accelerator operating in the "bubble" regime undergo strong periodic oscillations about the wakefield axis because of the focusing force provided by the ions. This betatron motion of the off-axis electrons results in the emission of x-ray radiation strongly peaked in the forward direction. Even though the x-rays are broadband with a synchrotron-like spectrum, their brightness can be quite high because of their short pulse duration and strong collimation. We employ particle tracking in particle in cell simulations with OSIRIS*, combined with a post-processing radiation diagnostic, to evaluate the features of the radiation mechanisms of accelerated electrons in LWFA experiments. We show and discuss results for a 1.5 GeV laser wakefield accelerator stage. A study of the angular dependence of the radiated power is also presented and compared with theoretical models. This analysis also allows for the direct calculation of the radiation losses of the self-injected bunch.

*R. A. Fonseca et al, LNCS 2329, III-342, Springer-Verlag, (2002)

• D.A. Jaroszynski, M.P. Anania, E. Brunetti, S. Chen, S. Cipiccia, B. Ersfeld, J. Gallacher, M.R. Islam, R.C. Issac, G. Raj, A. J. W. Reitsma, R.P. Shanks, G. Vieux, G.H. Welsh, S.M. Wiggins
  USTRAT/SUPA, Glasgow
• R.A. Bendoyro, J.M. Dias, F. Fiuza, N. Lemos, M. Marti, J.L. Martins, L.O. Silva
  Instituto Superior Tecnico, Lisbon
• N. Bourgeois
  University of Oxford, Oxford
• P.S. Foster, R. Pattathil
  STFC/RAL, Chilton, Didcot, Oxon
• S.M. Hooker, T. Ibbotson
  University of Oxford, Clarendon Laboratory, Oxford
• D. Maneuski, V. O'Shea
  University of Glasgow, Glasgow

Funding: EPSRC and EU Euroleap

Advances in laser-plasma wake field accelerators (LWFA) have now reached the point where they can be considered as drivers of compact radiation sources covering an large spectral range. We present recent results from the Advanced Laser Plasma High-energy Accelerators towards X-rays (ALPHA-X) project. These include the first ultra-compact gamma ray source producing brilliant 10fs pulses of x-ray photons > 150keV. We present new opportunities for harnessing laser-driven plasma waves to accelerate electrons to high energies and use these as a basis for ultra-compact radiation sources with unprecedented peak brilliance and pulse duration. We have demonstrated a brilliant tabletop gamma ray source based on enhanced betatron emission in a plasma channel which produces > 10⁹ photons per pulse in a bandwidth of 10-20%. We present results of a compact synchrotron source based on a LWFA and undulator and discuss the potential of developing an FEL based this technology. Finally we discuss the plans for the Scottish Centre for the Application of Plasma-based Accelerator (SCAPA), which is being set up to develop and apply compact radiation sources, laser-driven ion sources and LWFAs.