Magnetized relativistic jets and helical magnetic fields - I. Dynamics I. Moya-Torregrosa, A. Fuentes, J. M. Martí, J. L. Gómez and M. Perucho A&A, 650 (2021) A60 Published online: 08 June 2021 DOI: 10.1051/0004-6361/202037898