Posted: Tue May 13, 2003 6:06 am
Fusion refers to the fusing of light atomic nuclei into heavier nuclei to release energy. Currently nuclear powerplants use fission: breaking apart heavy nuclei into lighter nuclei to release energy. Medium sized nuclei are the most stable, and tremendous energy is released in breaking apart heavy nuclei and fusing together light nuclei. Uranium is used in nuclear power plants now because it is easy to set up a fission chain reaction to keep the plant working properly.
Fusion is of course the process that powers the sun and all other stars. Hydrogen nuclei fuse together into helium nuclei, converting some small amount of mass into energy in the process. In stars, this occurs because of the high amounts of gravitational force pushing all the matter together, creating high levels of heat and pressure.
Currently there is research in using fusion to generate power on earth. Most of this research is in recreating fusion as it is done in stars, on a much smaller scale. Heavy hydrogen nuclei (they are heavy because they have more neutrons) are put into conditions made to simulate those in stars, allowing them to fuse into helium. This takes lots of energy to generate the temperatures at which fusion takes place, and currently the energy required to cause the fusion is much greater than the energy released by the fusion reaction. The goal of the research is to produce a fusion reactor where a fusion reaction can be started, the high energy plasma contained by magnetic fields, such that the energy produced is greater than the energy required to start the reaction, so power can be generated and put to use.
Cold fusion is an alternative way of trying to use fusion to get energy. The idea is that instead of recreating the conditions of a star, fusion is caused to occur by some alternative means not involving such high temperatures. In the late 80's, some scientists reported success in getting fusion to occur at room temperature in test tubes. But the effect was small and hard to reproduce and not well understood, so lots of scientists say that it isn't really fusion or that the effect didn't exist or something like that, and the scientific community ended up mostly losing interest in it. More recently there have been attempts to cause fusion using soundwaves, and this has apparently been more accepted. But cold fusion just isn't well understood, so it hasn't received as much support in the scientific community as efforts to replicate the conditions inside of stars which is better understood since we think we have some idea how the sun works.
Cold fusion isn't a theory. It refers to any sort of fusion that takes place in conditions where temperatures are less that that of a star (ie room temperature). And there have been at least these two approaches taken to getting it to happen. Scientists haven't dropped the theory, there are still scientists researching these approaches and probably others as well. It just isn't a popular field, since it isn't well understood.
Fusion is of course the process that powers the sun and all other stars. Hydrogen nuclei fuse together into helium nuclei, converting some small amount of mass into energy in the process. In stars, this occurs because of the high amounts of gravitational force pushing all the matter together, creating high levels of heat and pressure.
Currently there is research in using fusion to generate power on earth. Most of this research is in recreating fusion as it is done in stars, on a much smaller scale. Heavy hydrogen nuclei (they are heavy because they have more neutrons) are put into conditions made to simulate those in stars, allowing them to fuse into helium. This takes lots of energy to generate the temperatures at which fusion takes place, and currently the energy required to cause the fusion is much greater than the energy released by the fusion reaction. The goal of the research is to produce a fusion reactor where a fusion reaction can be started, the high energy plasma contained by magnetic fields, such that the energy produced is greater than the energy required to start the reaction, so power can be generated and put to use.
Cold fusion is an alternative way of trying to use fusion to get energy. The idea is that instead of recreating the conditions of a star, fusion is caused to occur by some alternative means not involving such high temperatures. In the late 80's, some scientists reported success in getting fusion to occur at room temperature in test tubes. But the effect was small and hard to reproduce and not well understood, so lots of scientists say that it isn't really fusion or that the effect didn't exist or something like that, and the scientific community ended up mostly losing interest in it. More recently there have been attempts to cause fusion using soundwaves, and this has apparently been more accepted. But cold fusion just isn't well understood, so it hasn't received as much support in the scientific community as efforts to replicate the conditions inside of stars which is better understood since we think we have some idea how the sun works.
Cold fusion isn't a theory. It refers to any sort of fusion that takes place in conditions where temperatures are less that that of a star (ie room temperature). And there have been at least these two approaches taken to getting it to happen. Scientists haven't dropped the theory, there are still scientists researching these approaches and probably others as well. It just isn't a popular field, since it isn't well understood.