Monte Carlo analysis of ionization effects on spatiotemporal electron swarm development Saša Dujko, Zoran M. Raspopović, Ronald D. White, Toshiaki Makabe and Zoran Lj. Petrović Eur. Phys. J. D, 68 6 (2014) 166 Published online: 27 June 2014 DOI: 10.1140/epjd/e2014-50088-4