Naked Science Forum

General Science => General Science => Topic started by: Joe L. Ogan on 10/01/2010 20:42:32

Title: In Fusion, does the energy come from protons, electrons or neutrons?
Post by: Joe L. Ogan on 10/01/2010 20:42:32

In Fusion, does the energy come from protons, electrons, or neutrons?  Do they fuse a mass of atoms?  Just exactly how does the energy occur?  Is it related to the quark?
Do ions play a part in the energy process?  Thanks for comments.  Joe L. Ogan

Title: In Fusion, does the energy come from protons, electrons or neutrons?
Post by: graham.d on 11/01/2010 14:22:26

Fusion involves the overcoming the electrostatic repusion between two atomic nuclei so as to produce a third atomic nucleus plus (usually) the release of other particles. The energy released is because the final nuclear state is at a lower energy than the sum of the initial states. Because it is necessary to overcome the long range electrostatic repulsion, to allow the strong nuclear (attractive) force to take over, very high temperatures are required to provide nuclei with sufficient kinetic energy. The electron shells play no significant part (as far as I know). In any case in Tokomak reactors the atoms are ionised (as plasma) because the temperatures are so very high.

There are many possible fusion reactions and the object, rather crudely, is to produce heat to ultimately drive steam turbines. Most fusion reactions produce energetic neutrons as well as heat and these are captured by absorption in surrounding material to generate more heat. The problem with this is that the neutron flux eventually degrades the material and leaves it radioactive. Other reactions do not do this and there are trade offs to be made between the relative difficulty of managing the neutron flux and the difficulty of attaining the temperatures needed to sustain the particular fusion reactions fpr a particular required power output.