Asymmetric lateral coherence of betatron radiation emitted in laser-driven light sources B. Paroli, E. Chiadroni, M. Ferrario, V. Petrillo, M. A. C. Potenza, A. R. Rossi, L. Serafini and V. Shpakov EPL, 111 4 (2015) 44003 Published online: 04 September 2015 DOI: 10.1209/0295-5075/111/44003