  A characteristic signature of quark confinement is the concentration of the
chromoelectric field between a static quark-antiquark pair in a flux tube.
However, the structure of this flux tube, and hence of the confining force, has
not been completely understood. Here we perform new lattice measurements of
field distributions on smeared Monte Carlo ensembles in SU(3) gauge theory. On
the basis of these simulations we demonstrate that the confining force can be
understood using the analogy with the basic principles of electromagnetism as
elucidated by Maxwell. We derive a chromomagnetic Lorentz force density
coupling the chromoelectric field to chromomagnetic currents and integrate this
force density over the flux tube interior to obtain a Maxwell-like force that
squeezes the flux tube in the transverse direction. We show that the strength
of this transverse confining force is equal to the value of the string tension
calculated numerically from the chromoelectric field on the midplane between
the quarks, verifying the consistency of these two complementary pictures of
confinement.
