  A mechanism of generation of a toroidal component of large scale magnetic
field, leading to the reconstruction of the pulsar magnetospheres is presented.
In order to understand twisting of magnetic field lines, we investigate
kinematics of a plasma stream rotating in the pulsar magnetosphere. Studying an
exact set of equations describing the behavior of relativistic plasma flows,
the increment of the curvature drift instability is derived, and estimated for
$1s$ pulsars. It is shown that a new parametric mechanism is very efficient and
can explain rotation energy pumping in the pulsar magnetospheres.
