Dynamics of pick-up ions in collisionless velocity shears E. Pérez-Tijerina, M. Reyes-Ruiz, H. Pérez-de-Tejada and H. Durand-Manterola A&A, 388 2 (2002) 667-675 Published online: 31 May 2002 DOI: 10.1051/0004-6361:20020128