Assuming the current best-fit solutions to the solar neutrino problem at
large mixing angle, we briefly illustrate how prospective data from the Sudbury
Neutrino Observatory (SNO) and from the Kamioka Liquid scintillator
Anti-Neutrino Detector (KamLAND) can increase our confidence in the occurrence
of standard matter effects on active neutrino flavor oscillations in the Sun,
which are starting to emerge from current data.Comment: Updated to include the first KamLAND data. One figure adde