Helioseismic constraints on the solar structure and the solar neutrino problem

The inversion of helioseismic modes leads to precise constraints on the int ernal structure of the Sun, which must be satisfied by the computed solar m odels. Including the element segregation which occurred in the Sun since it s formation leads to solar models in much better agreement with the inversi on structure than those which ignore it. However the observed lithium deple tion cannot be explained without other effects like mild mixing below the c onvection zone, or rapid mass loss in the early stages of the solar evoluti on. In any case the models are not compatible with the observed neutrino fl uxes. Mixing near the solar core, which has been invoked as a way of decrea sing the neutrino production, can be infirmed by helioseismic results. Thes e results will be discussed and solar models close to the "Seismic Sun" wil l be presented.