Experimental evidence of radiation reaction in the collision of a high-intensity laser pulse with a laser-wakefield accelerated electron beam

• Published in: arXiv.org 2018-01
• Main Authors: Cole, J M, Behm, K T, Blackburn, T G, Wood, J C, Baird, C D, Duff, M J, Harvey, C, Ilderton, A, Joglekar, A S, Krushelnik, K, Kuschel, S, Marklund, M, McKenna, P, Murphy, C D, Poder, K, Ridgers, C P, Samarin, G M, Sarri, G, Symes, D R, Thomas, A G R, Warwick, J, Zepf, M, Najmudin, Z, Mangles, S P D
• Format: Article
• Language: English
• Subjects: Acceleration; Elastic scattering; Electromagnetic fields; Energetic particles; Energy dissipation; Energy measurement; High energy electrons; High power lasers; Laser beams; Lasers; Photons; Relativistic electron beams
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.1707.06821

The dynamics of energetic particles in strong electromagnetic fields can be heavily influenced by the energy loss arising from the emission of radiation during acceleration, known as radiation reaction. When interacting with a high-energy electron beam, today's lasers are sufficiently intense to explore the transition between the classical and quantum radiation reaction regimes. We report on the observation of radiation reaction in the collision of an ultra-relativistic electron beam generated by laser wakefield acceleration (\(\varepsilon > 500\) MeV) with an intense laser pulse (\(a_0 > 10\)). We measure an energy loss in the post-collision electron spectrum that is correlated with the detected signal of hard photons (\(\gamma\)-rays), consistent with a quantum (stochastic) description of radiation reaction. The generated \(\gamma\)-rays have the highest energies yet reported from an all-optical inverse Compton scattering scheme, with critical energy \(\varepsilon_{\rm crit} > \) 30 MeV.