Polarisation of a small-scale cometary plasma environment - Particle-in-cell modelling of comet 67P/Churyumov-GerasimenkoHerbert Gunell, Jesper Lindkvist, Charlotte Goetz, Hans Nilsson and Maria HamrinA&A, 631 (2019) A174DOI: https://doi.org/10.1051/0004-6361/201936004