  We investigate the nonlinear Meissner effect microscopically. Previous
studies did not consider a certain type of interaction effect on the nonlinear
phenomena. The scattering amplitude barely appears without being renormalized
into the Fermi-liquid parameter. With this effect we can solve the outstanding
issues (the quantitative problem, the temperature and angle dependences). The
quantitative calculation is performed with use of the fluctuation-exchange
approximation on the Hubbard model. It is also shown that the perturbation
expansion on the supercurrent by the vector potential converges owing to the
nonlocal effect.
