#9 FAQ - How the fusor fuses, limitations and Stars

[Richard Hull]

I would put this FAQ in the theory forum but there is no FAQ banner there. The following FAQ is a copy of a response I gave the future of fusion forum.

All fusion in a fusor is accomplished by Quantum Tunneling....

My entanglement with quantum physics is limited to self-study. Only in the serach for a degree in physics would one receive a course in this branch of physics. I am limited to my time in college as an engineer.

We fuse mostly with high speed deuterons and or neutral deuterium atoms in collision in velocity space and not in a plasma.

The deuteron is an ion and is the deuterium atom stripped of its single electron.

The deuteron has an electrostatic charge of +1, chemically and ionically and so far as any future atomic nuclear reactions are concerned.

Similar electrical charges repel and, thus, deutrons repel each other as they get close to one another.

The closer deuterons get to each other the more intense the force to repel gets, such that they can never touch mechanically.

The fusor attempts to force deuterons to "collide" and fuse.

Earlier in the last century, when fusion was discovered ~1932, quantum mechanics was new. Part of the theory states that, given two ions (nuclei) heading towards each other at some collisional energy, X, there is some probability, Y, that the potential barrier represented by the columbic repulsion will be "tunneled through" at a quatum level deep enough to have the "nuclear strong force" grab on to, or overcome the columbic force, thus, fusing the deuterons together. It is all more mathematically complex than this, but this is the upshot of how all fusion is done. That's 100% of all fusion.

This is the sticking point in all fusion attempts! You have to supply enough seed energy, (tremndous amount), to attempt to get enough deuterons up to energy inorder to have enough probability of fusing enough atoms to just equal or surpass the seed energy. The equation governing this complex relationship is referred to as the "Lawson criteria"

An analogy of failed fusion or fusion in our fusors and all other fusion reactors to date, follows..........

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Jimmy pays 1 cent for each chance to throw three, ten-sided dice. Each time they total 30 he is a winner and given a dollar. He furiously throws the dice for 10,000 times and winds up with $28.00. He spent 10,000 pennys, $100.00, to get $28.00. Sure! You guessed it. The game is rigged by unresolvable probabilties stacked against him. What is the probability he will spend a dollar in pennies and walk away with $100.00? Ha! This analogy is not perfect, but shows fusion for what it is......a dice game.

In stars, once born, there is always a Jimmy, (gravitaional energy), rolling the dice! Thanks to a virtually inexhaustable supply of pennys (hydrogen atoms) the game virtually never ends. Naturally, due to probability, Jimmy wins a certain amount and a large number of dollars, (taken from his pennies), are sent home to mom and the family....(Fusion energy sent out into space to warm and illuminate planets to support life). However, all those penny's spent on jimmy's rolls that were not winners, recycle into Jimmy's supply of future available pennys for new rolls of the dice.

Jimmy lives for billions of years until he exhausts his penny supply by winning enough to deplete his stash of coins. In frustration, he goes apoplectic and explodes.

Were the odds different, (nature's laws of fusion physics), and the game used two, two-sided dice and a four resulted in a $4,000,000 payout from his penny supply, the game would be over, (the universe would end), in a twinkling. Lucky for jimmy and the folks back home, (and the universe), the rules were made up for born suckers such that Jimmy would game his heart out for billions of years and mom would have a long and steady income.

Jimmy was never in it to win, over the long haul. He was in it to play the game and to support mom and the folks back home. The reason he even lived so long was that he lost so often that the bulk of his expenditures stayed with him. Only his winnings, a tiny fraction of his reserves, ever left.

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We've done fusion in our fusor as noted above by smashing through the potential barrier in some small fraction of the rolls of the quantum dice. What now....?

Now our two deuterons are fused. But wait! All is not over! The reaction is unstable once it occurs, even though the two protons and two neutrons from the crashed and fused nuclei equal the nucleus of one of the most stable atoms, standard balloon helium 4He. The fused nuclei form a 50:50 probable outcome. In one reaction, a triton, (tritium nuclei), is formed along with a free flying proton. In the other reaction, the very rare 3He, (bizarre helium), is formed along with a free flying neutron. Only once in about every 10,000 deuterium-deuterium fusions will a single 4He, (balloon helium), atom be the result. Don't ask me why, it is just the observed result.

I have given my best stab at a simple explanation of quantum tunneling. It is a probabalistic reaction, based on the nuclear cross sections of the nuclei at a specific collisional energy. The cross sections are an empirically arrived at, effective diameter of the colliding nuclei. The bigger the cross section, the more likely it is that fusion and quantum tunnelling will occur.

This is all part of the understanding that the lay mind rarely has contact with or in which a real understanding is attempted to be given

Richard Hull