Flux tubes in Nf = 2 + 1 QCD with external magnetic fields Claudio Bonati, Salvatore Calì, Massimo D’Elia, Michele Mesiti, Francesco Negro, Andrea Rucci and Francesco Sanfilippo EPJ Web Conf., 175 (2018) 12008 Published online: 26 March 2018 DOI: 10.1051/epjconf/201817512008