Solar wind parameters from the Massachusetts Institute of Technology (MIT) plasma experiment on the IMP 8 spacecraft overlap similar to 19 years of published neutrino flux observations from the Homestake experiment. A strong correlation is found between neutrino flux and solar wind properties, in particular, the solar wind mass flux. The correlation is significantly better than any anticorrelation with sunspot number and is comparable to those previously found with photospheric magnetic flux and shifts in p-mode frequencies. If current notions of solar structure are correct, these observations require new fundamental physics of neutrinos. For a proper choice of neutrino parameters, the level of variations is consistent with resonant conversion of electron neutrinos to a nondetected flavor eigenstate mediated by the magnetic field in the sun’s convective zone. The solar wind mass-flux may act as a proxy for this field, producing the solar wind-neutrino flux connection.