Vacuum, confinement, and QCD strings in the vacuum correlator method

QCD vacuum properties and the structure of color fields in hadrons are reviewed using the complete set of gauge-invariant gluon field correlators. QCD confinement is produced by correlators with a certain Lorentz structure, which violate the Abelian Bianchi identities and are therefore absent in QED. These correlators are used to define an effective colorless field satisfying the Maxwell equations with a nonzero effective magnetic current. In the language of correlators and the effective field, it is shown that non-Abelian interaction of gluon gauge fields leads to quark confinement due to effective circular magnetic currents that squeeze gluon fields into a string in accordance with the 'dual Meissner effect'. Distributions of effective gluon fields in mesons, baryons, and glueballs with static sources are plotted.