  The quark production in classical color fields is investigated with a focus
on the induction of an electromagnetic current by produced quarks. We show that
the color SU(2) and the SU(3) theories lead significantly different results for
the electromagnetic current. In uniform SU(2) color fields, the net
electromagnetic current is not generated, while in SU(3) color fields the net
current is induced depending on the color direction of background fields. Also
the numerical study of the quark production in inhomogeneous color fields is
done. Motivated by gauge field configurations provided by the color glass
condensate framework, we introduce an ensemble of randomly distributed color
electric fluxtubes. The spectrum of photons emitted from the quarks by a
classical process is shown.
