  Homestake, Gallex and GNO data reveal variability of the solar neutrino flux.
Kamiokande records for 1996-2001 reveal oscillations at 9.43 and 12.6
yr$^{-1}$, well within a range (6-16 yr$^{-1}$) that, according to
helioseismology, may be related to internal solar rotation. A nuclear-decay
experiment at Brookhaven National Laboratory (for 1982-86) reveals strong
oscillations at 11.2 and 13.2 yr$^{-1}$. Similar oscillations are found in
nuclear-decay measurements conducted by A. Parkhomov. By contrast, S. Pomme
points out that nuclear-decay experiments at standards laboratories tend not to
exhibit variability. The most extensive series of nuclear-decay measurements
comes from an experiment initiated by G. Steinitz at the Geological Survey of
Israel (2007-16), which recorded 340,000 radon-related measurements from each
of 3 gamma detectors and 3 environmental sensors. Analysis of a subset of
85,000 hourly gamma measurements reveals a number of oscillation frequencies
compatible with influences of internal solar rotation. There is no correlation
between the gamma and environmental measurements. The solar internal magnetic
field may lead to neutrino modulation by the RSFP (Resonant Spin-Flavor
Precession) mechanism. A triplet of oscillations (7.43, 8.43 and 9.43
yr$^{-1}$) may be attributed to an internal region (presumably the core) with a
sidereal rotation rate of 8.43 yr$^{-1}$ and a rotation axis roughly orthogonal
to that of the photosphere. This suggests that the Sun had its origin in more
than one stage of condensation of interplanetary material (one on top of
another), which could lead to present-day layers with different metallicities,
rotation rates and axes. The peak modulation occurs near local midnight in
early June, suggestive of a role of cosmic neutrinos. These neutrinos could
provide the mass attributed to dark matter for a neutrino mass of order 0.1 eV.
