(First published on June 13, 2014. This page will be updated with the addition of reference material)

I've been following for 15 years the Allais effect (Foucault pendulum that goes wrong during the eclipses of the sun). I have spent time and money making equipment and experiments, believing that it was worth it. The widespread opinion among a group of fans (including me and NASA ), independent or affiliated to institutions, was that this effect had something mysterious not easily understandable in the frame of commonly accepted physics. On this subject,  articles have been published in various forms of literature, including articles in major peer-reviewed journals (Nature, Physical Review, etc..., as well as arXiv, internet and more), accompanied by various hypotheses . I myself have advanced some hypotheses that proved unfounded.

Mystery until last year. I had suspended my experiments, because I already had enough to speculate on the data I had collected, but indeed even for unavoidable reasons. And some foreign friends suspended their experiments too, for various reasons, but one. Prof. Alexander Pugach, of the National Academy of Sciences of Ukraine, continued to collect data nearly continuously until last January. He has published several articles in which he claims to have observed anomalous behavior of his instrument (described briefly further down) in conjunction with solar eclipses . His articles are credible, as around solar eclipses actually a strange behavior is observed in a family of devices that have the common feature of having a freedom of movement around a pivot point (pendulums, spring-mass gravimeters, torsion balances) . I have some personal achievements too, of which I am absolutely certain, that confirm the anomaly. There are several peer-reviewed articles that confirm the anomaly, but they lack any solid explanation.

In my opinion, solar eclipses have nothing to do with these anomalies. What plays the game is a concomitant circumstance, contemporary or more or less shifted with respect to the optical eclipe. I am referring to the vacuum of solar wind that occurs on the anti-sunward side of the moon, which is well known as lunar wake. I have come to this conclusion, that I'm going to illustrate, around the end of 2013.
I have to say that Pugach has authorized me to use his data publicly, because he honestly recognizes my priority on the discovery of the correlation. Pugach often sent me his data, most often in recent times.

Let's briefly describe the apparatus, which Pugach calls torsind (torsion indicator). It is a thin aluminum disc of about 12 cm in diameter, weight 0.1g, suspended in the center via a single strand of natural silk, closed in a sealed container but not empty of air, electrostatically but not magnetically shielded, with an automatic monitoring system of the azimuth of a reference on the disc. The system was in an isolated environment, away from people and electrical noise in an closed unattended ambient, etc ...
During eclipses of the sun, this disc rotated some little. This during periods of calm sun. With the passage of time (which "a posteriori" means practically with the approach of maxima in this solar cycle) the disc rotated sometimes in the absence of eclipses. The more time passed, the more this happened . From Pugach's data and sunspot number data, I saw that there was a gross correlation over the long period between the two things . But in the short term there was no correlation. I told Pugach this. Nothing clear at that time, only a rough correlation and no idea of the mechanism.

At one point I had the intuition that for some reason some eddy currents could arise in the disk, with associated magnetic fields and associated effects (such as the disk of old style utility meters).
I began to consider the magnetosphere and to study its interaction with the solar wind.
In summary, the already known situation is this:
The solar wind is always present, and is responsible for the shape of the magnetosphere . Under conditions of quiet sun the solar wind is uniform and the magnetosphere is quiet, without disruption of the equilibrium of electrical currents and of lines of force of the Earth's magnetic field which pervades it. When there is solar activity, the solar wind can be disturbed, with accelerated and diverted gusts and more. This occurs in coarse correlation with the sunspot number, but not always the solar wind disturbances do hit the Earth. The sun emits the wind all around, and only if a disturbance is emitted in a favorable direction it would reach Earth. The solar wind is blocked by the magnetosphere, as it is well known, and a non-uniform wind is likely to cause geomagnetic storms and other minor geomagnetic disturbances. A non-uniform solar wind disturbs the tranquility of the magnetosphere.
I needed to find data on geomagnetic activity to be correlated to the Pugach's data, and I found them in NOAA archives with respect to geostationary satellites carrying magnetometers on board.

The correlation was striking. In January, the rotations of the disk due to geomagnetic activity were orders of magnitude greater than the rotations observed during solar eclipses in periods of calm sun. In such conditions as in January a solar eclipse would not be "seen" by a torsind, being much under, say, the noise level.

 

So what happens during an eclipse (with calm sun)? It is easy. The lunar wake causes a localized imbalance in the magnetosphere. I found traces of the lunar wake in satellite data in correspondence of eclipses in periods of calm sun in which Pugach had detected rotations of his torsind, and in correspondence of anomalies that I had detected with a stationary pendulum during an eclipse.
Perhaps it is unnecessary to mention it, but in order for currents to be induced in the measuring instrument, it is necessary that the instrument passes through magnetic gradients steep enough. As can be seen from satellite data, such circumstances occur during geomagnetic storms, and to a lesser extent and with rather local characteristics, during solar eclipses.
That said, the Allais effect is no longer a mystery to me, and I must also say that I am a bit disappointed, because I had recently purchased a number of devices to improve myself in the measurements.
In the end, a disappointing banality!

Antonio Iovane