  The partial reflection of an electromagnetic (EM) wave from a medium leads to
absorption of momentum in the direction perpendicular to the surface (the
standard radiation pressure) {and, for oblique incidence on a partially
reflecting medium}, also in the parallel direction. This latter component
drives a transverse current and a slowly growing, quasi-static magnetic field
in the evanescence ``skin'' layer. Through a simple model we illustrate how EM
momentum is transfered to ions and estimate the value of the magnetic field
which may be of the order of the driving EM wave field, i.e. up to several
hundreds of megagauss for high intensity laser-solid interactions.
