  We compute the electromagnetic fields generated in heavy-ion collisions by
using the HIJING model. Although after averaging over many events only the
magnetic field perpendicular to the reaction plane is sizable, we find very
strong magnetic and electric fields both parallel and perpendicular to the
reaction plane on the event-by-event basis. We study the time evolution and the
spatial distribution of these fields. Especially, the electromagnetic response
of the quark-gluon plasma can give non-trivial evolution of the electromagnetic
fields. The implications of the strong electromagnetic fields on the hadronic
observables are also discussed.
