  First I emphasize the magnetospheric loop current system induced by the wind
activity. Next, I address the formation of the field-aligned electric field. An
interesting aspect is the reaction of the inner magnetosphere to an induced
current. In the traditional outer gap, the current running through the gap is
all carried by the particles created in the gap. However, if external
current-carrying particles are added, the gap moves inward or outward; it can
even appear near the star. It is suggested that the gaps appear at various
altitudes, depending on the current distribution on field lines, the field line
geometry, and the source of the current-carrying particles.
  For definiteness of sign of charge and current direction, $\vec{\Omega} \cdot
\vec{\mu} >0$ is assumed throughout.
