... and cold fusion

22. Lightning melts Metals; and I hinted in my Paper on that Subject, that I suspected it to be a cold Fusion (I do not mean a Fusion by Force of Cold, but a Fusion without Heat.)

-- Benjamin Franklin, second letter to Peter Collison dated July 29, 1750

[This is the third post in a series; the first is here.]

The man who coined the phrase "cold fusion" was none other than Benjamin Franklin, in connection with his experiments on electricity and lightning. The phrase is generally taken to mean that Franklin found static electricity capable of inducing changes in metal much like melting, but without producing the sensible heat that would normally have accompanied the process. As the foremost student of lightning of his day, there is a reasonable possibility he saw ball lightning or other plasmoid phenomena. We know that German physicist Georg Wilhelm Reichmann, attempting to replicate Franklin's famous kite experiment the following year, did. Briefly. "A glowing ball of charge traveled down the string, jumped to his forehead and killed him instantly - providing history with the first documented example of ball lightning in the process." (APS)

Observed ball lightnings tend to range from fist to furniture sized. This is probably more an observer selection effect than a physical one. We know that latter-day experiments by Bostick, Shoulders, Matsumoto, Adamenko, Jaitner, and others have produced condensed plasmoids with sizes (and characteristic tracks) range down to the 50 micron range, requiring microscopes to see their structure. 

Cold fusion, in Franklin's sense, definitely appears to be going on when a plasmoid touches down on to matter, be it metal or dielectric. Condensed plasmoids (hereinafter CPs) disrupt matter very much as super-highly charged ions do, by yanking electrons off atoms, removing bonds and causing the atoms to repel each other electrostatically. 

Here are two photos from Ken Shoulders' work showing holes made in lead glass and aluminum respectively by CPs.  

In these pictures, CPs have drilled through an aluminum coating and into a slab of alumina (Al2O3, a very hard ceramic and the primary constituent of ruby and sapphire), spewing alumina back out the holes in such a way as to form a patchy coating on the aluminum.

It's pretty clear that ionic disruption, not heat, is the causative agent here, so we have cold fusion in Franklin's sense. What about the more modern sense of nuclear reactions? Here is a micrograph of a similar hole in a deuterium-loaded palladium foil. Although most of the foil remained pure palladium, the gunk around the hole(s) evidenced significant amounts of silicon, calcium, and magnesium.

So what's going on? The theory is that CPs form when a spark, ranging from rubbing a cat and touching a doorknob to lightning, finds just the right conditions for a runaway ζ-pinch which magnetically squeezes the plasma to atomic scales. Considered in isolation, a current like that hanging in free space really wants to form a loop, since it's creating a major positive charge at one end and a negative one at the other, and the ends thus attract. When the ζ-pinch runs away it's capable of squeezing nuclei together close enough for tunneling to happen, and what happens then depends on what nuclei happen to have gotten trapped in there.

What happens then is problematical if only because there are so many possibilities depending on both the environment and the configuration of the CP. But it seems that in come cases, especially in metal, the CP can dig itself a "nest" which both stabilizes it and provides it with fusion fuel (e.g. deuterons with which a palladium electrode has been loaded, that seep out into the CP sustaining an ongoing reaction). Evidence for this is that electrodes that have exhibited cold fusion tend to be easier to start it up again than fresh ones, presumeably because the "nests" are already there and easier to form CPs in.