  We present an analytic derivation of the temporal dependence of the
perpendicular transport coefficient of charged particles in magnetostatic
turbulence, for times smaller than the time needed to charged particles to
travel the turbulence correlation length. This time window is left unexplored
in most transport models. In our analysis all magnetic scales are taken to be
much larger than the particle gyroradius, so that perpendicular transport is
assumed to be dominated by the guiding center motion. Particle drift from the
local magnetic field lines and magnetic field lines random walk are evaluated
separately for slab and 3D isotropic turbulence. Contributions of wavelength
scales shorter and longer than the turbulence coherence length are compared. In
contrast to slab case, particles in 3D isotropic turbulence unexpectedly
diffuse from local magnetic field lines; this result questions the common
assumption that particle magnetization is independent on turbulence geometry.
Extensions of this model will allow for a study of solar wind anisotropies.
