  In previous experiments by the authors on a magnetic dipole interacting with
a laser-produced plasma the generation of an intense field-aligned current
(FAC) system on terrella poles was observed. In this paper the question of the
origin of these currents in a low-latitude boundary layer of magnetosphere is
investigated. Experimental evidence of such a link was obtained by measurements
of the magnetic field generated by tangential drag and sheared stress. This
specific azimuthal field was found to have quadruple symmetry and local maxima
inside the magnetosphere adjacent to the boundary layer. Cases of metallic and
dielectric dipole covers modeling good conductive and non-conductive ionosphere
revealed that the presence or absence of FACs results in different amplitudes
and spatial structures of the sheared field. The current associated with the
azimuthal field flows upward at the dawnside, and toward the equator plane at
the duskside. It was found to coincide by direction and to correspond by
amplitude to a total cross-polar current measured independently. The results
suggest that compressional and Alfven waves are responsible for FAC generation.
The study is most relevant to FACgeneration in the magnetospheres of Earth and
Mercury following pressure jumps in solar wind.
