Measurement of the polarisation in the auroral N2+ 427.8 nm band Mathieu Barthelemy, Hervé Lamy, Anne Vialatte, Magnar Gullikstad Johnsen, Gaël Cessateur and Naïma Zaourar J. Space Weather Space Clim., 9 (2019) A26 Published online: 16 July 2019 DOI: 10.1051/swsc/2019024