  The mechanism of non-Abelian color confinement is studied in SU(2) lattice
gauge theory in terms of the Abelian fields and monopoles extracted from
non-Abelian link variables without adopting gauge fixing.
  Firstly, the static quark-antiquark potential and force are computed with the
Abelian and monopole Polyakov loop correlators, and the resulting string
tensions are found to be identical to the non-Abelian string tension. These
potentials also show the scaling behavior with respect to the change of lattice
spacing.
  Secondly, the profile of the color-electric field between a quark and an
antiquark is investigated with the Abelian and monopole Wilson loops. The
color-electric field is squeezed into a flux tube due to monopole supercurrent
with the same Abelian color direction. The parameters corresponding to the
penetration and coherence lengths show the scaling behavior, and the ratio of
these lengths, i.e, the Ginzburg-Landau parameter, indicates that the vacuum
type is near the border of the type1 and type2 (dual) superconductor.
  These results are summarized that the Abelian fundamental charge defined in
an arbitrary color direction is confined inside a hadronic state by the dual
Meissner effect. As the color-neutral state in any Abelian color direction
corresponds to the physical color-singlet state, this effect explains
non-Abelian color confinement and supports the existence of a gauge-invariant
mechanism of color confinement due to the dual Meissner effect caused by
Abelian monopoles.
