  In this paper, we show how one can change the stable equilibrium of a
particle trapped into an optical tweezer by varying the intensity of superposed
Bessel beams with different orders. The gradient forces acting on particles of
different radii are determined, and the theoretical results indicates that it
is possible to combine Bessel beams in such a way as to manipulate the particle
into or out the centre of the beam by exploiting their ring-shaped intensity
patterns, without any mechanical displacement of the lasers.
