Inference of the chromospheric magnetic field orientation in the Ca ii 8542 Å line fibrils A. Asensio Ramos, J. de la Cruz Rodríguez, M. J. Martínez González and H. Socas-Navarro A&A, 599 (2017) A133 Published online: 14 March 2017 DOI: 10.1051/0004-6361/201629755