Cold Fusion? Is it possible?

[Fusion_power]

(No, this is NOT about shipping me to the north pole)

Just for fun, I'd be interested in opinions re the feasibility of cold fusion becoming a viable technology. Cold fusion is defined as combining nuclei at temperatures less than the millions of degrees required for example in a fusion bomb. I won't go into the details of Pons and Fleischman's fiasco of several years ago. Here are some thoughts:

1. There are three basic forces to contend with: Gravity, Electro-weak, and strong nuclear. The first two impact at the distance squared, the last at the distance cubed.

2. Fusion can only occur if the strong nuclear force is overcome such that two separate nuclei combine to become one with release of energy to get rid of the excess mass.

3. Heavier isotopes have more mass therefore are easier to manipulate. Deuterium and Tritium isotopes of hydrogen are the best candidates for cold fusion to occur.

A basic comparison can be made to a candle where the wax is consumed as it flows up the wick. It is first liquified, then gassified, then oxidized to release heat and light. Note that the candle does not work at all without the wick, just try to light the raw wax without one. What would constitute a "wick" for hydrogen?

Fusion (the man, not the cold version)

[ewmayer]

Originally Posted by Fusion_power

3. Heavier isotopes have more mass therefore are easier to manipulate. Deuterium and Tritium isotopes of hydrogen are the best candidates for cold fusion to occur.

Deuterium and Tritium aren't used in earthbound fusion experiments because they're more massive than bare Hydrogen nuclei (i.e. protons) per se, but rather because they allow fusion to occur via a more-direct and simpler (and hence easier to initiate) process than the complex one that occurs deep in the cores of stars. In stars, you start with 4 hydrogen atoms (or 4 protons and 4 electrons - the temperature is much too high for the electrons to remain bound to the protons), and via a complex series of steps, two of the protons have to combine with 2 electrons to form 2 neutrons, which together with the remaining 2 protons and 2 electrons constitute (in still-ionized form) a Helium-4 atom. That process is much too complex and slow too attempt to duplicate in earthbound laboratories, so we bypass the neutron-generating step by using deuterium and the even more neutron-rich, but alas radioactive, tritium, which has to be produced in atomic reactors or via neutron irradition of deuterium in a particle beam.

As you say, the main barrier to low-temperature fusion is the Coulomb repulsion of the positively charged atomic nuclei - one of the reasons doubt was cast on Pons & Fleischman's "discovery" is that they never provided (nor did anyone else find) a plausible physical mechanism for how any low-T process could overcome this incredibly strong repulsive force.

The only form of "cold" fusion that IS known to occur involves getting the nuclei closer together by reducing the SIZE of the atoms involved. This can be done by replacing the electrons in a normal atom by its heavier (but otherwise identical) cousin, the muon. This shrinks the atom by roughly a factor of 100, and allows fusion to occur at relatively modest temperatures - the phenomenon is known as "muon-catalyzed fusion." Using the even heavier third wheel of the triad, the tauon, would be even better, but those are even more unstable and harder-to-produce than muons. And unfortunately, no has found a practical way to produce huge quantities of muons and get them to combine with nuclei without using way more energy than the fusion of the resulting "muonated" atoms would produce.

[ColdFury]

1. There are three basic forces to contend with: Gravity, Electro-weak, and strong nuclear. The first two impact at the distance squared, the last at the distance cubed.

I thought the electro-weak force (IE, the united electromagnetic and weak force) only manifested itself at extremely high temperatures. Far, far beyond the heat necessary for fusion? And from what I've read, I thought gravity isn't a signifigent force at atomistic scales, electromagnetism far dominating it.

As an aside, I've never been able to find "simple" formulas for the strength of the strong nuclear and weak force. Am I correct in believing they can't be described with simple formulas like gravity or electromagnestism can? I know they don't extend in infinite distance.

[Fusion_power]

Cold,

The electro-weak is a single field effect with different manifestations. At the atomic level we call it the weak nuclear and at the macro level we call it electro-magnetic. If I understand the physics, the high temperatures used to run tests were so the equations would integrate which proved the two forces should instead be only one.

Gravity is dramatically weaker than the electro-weak force. Consider that if you dumped 3 tons of electrons on the earth and they were unbalanced by an equivalent electrical force of protons, the earth would be flung out of orbit around the sun. (if you doubt, I'll post the math, its quite interesting and no I didn't think it up, its in a book I have)

Both gravity and the electro-weak diminish as the square of distance, the strong nuclear diminishes as the cube of the distance. This means the strong nuclear is totally in control at atomic distances except under extreme conditions but is almost totally unfelt at greater distances. Consider what happens in forming a black hole, the force of gravity becomes so extreme that it overwhelms the electro-weak causing atoms to collapse into neutrons then it overwhelmes the strong nuclear force causing the neutrons to collapse into ???? we don't know quite what but it is definitely a black hole.

So in the end, the weakest force is actually the most powerful of all.