  We study vacuum dynamics of SU(3) lattice gauge theory at finite temperature.
Using the lattice Schr\"odinger functional, SU(3) vacuum is probed by means of
an external constant Abelian chromomagnetic field. Our preliminary numerical
data suggest that, by increasing the strength of the applied external field,
deconfinement temperature decreases towards zero. This means that strong enough
Abelian chromomagnetic fields destroy confinement of color.
