  We discuss the essential role of the low-lying eigenmodes of the
Faddeev-Popov (FP) ghost operator on the confining color-Coulomb potential
using SU(3) quenched lattice simulations in the Coulomb gauge. The
color-Coulomb potential is expressed as a spectral sum of the FP ghost operator
and has been explored by partially summing the FP eigenmodes. We take into
account the Gribov copy effects that have a great impact on the FP eigenvalues
and the color-Coulomb potential. We observe that the lowest eigenvalue vanishes
in the thermodynamic limit much faster than that in the Landau gauge. The
color-Coulomb potential at large distances is governed by the near-zero FP
eigenmodes; in particular, the lowest one accounts for a substantial portion of
the color-Coulomb string tension comparable to the Wilson string tension.
