The velocity-magnetic field correlation in the solar wind low-frequency turbulence decreases with increasing distance from the sun. A 2 1/2-dimensional MHD numerical simulation has been set up in order to investigate the interaction between the solar wind current sheet and Alfv¿n waves, as a possible decorrelation mechanism. The equilibrium structure models the magnetic field rotation in a sector boundary. On such an equilibrium we have superposed a perturbation intended to represent Alfv¿nic fluctuations converging with opposite correlation on the two sides of the heliospheric current sheet. In consequence of the opposite correlation a source of compressive fluctuations, related to a locally nonsolenoidal velocity field, is localized inside the current sheet. Moreover, the relation B2=const is initially verified. During the time evolution the Alfv¿nic correlation is destroyed inside the current sheet and compressive fluctuations are generated. Two kinds of such fluctuations have been identified, according to the sign of the density-magnetic field intensity correlation. For &bgr;1. A different dynamical mechanism is at work in the homogeneous region, producing spectra different from those found in the current sheet; this mechanism has been identified as a parametric decay. Spectra of physical quantities show features similar to those observed in the solar wind turbulence, both in the region where the Alfv¿nic correlation is destroyed and in the region where it is conserved. ¿ American Geophysical Union 1996