Increasing energy coupling into plasma waves by tailoring the laser radial focal spot distribution in a laser wakefield accelerator - Genoud, G; Bloom, MS; Vieira, J; Burza, M; Najmudin, Z; Persson, A; Silva, LO; Svensson, K; Wahlstrom, C-G; Mangles, SPD (PHYSICS OF PLASMAS, 2013)