The amazing promises of science- nuclear fusion once again
A joke that almost every physicist no matter what age has known since the day of his studies deals with the promises made by nuclear fusion. It constitutes the most promising technology of the future-and would maintain this status forever. Already for 60 years the plasma physicist have articulated the hope that in 50years’ time mankind would have access to almost any desired amount of cheap, clean and environmentally friendly energy by means of nuclear fusion. Only that the time frame has not changed with progressing time. It stands at 50years since the middle of last century until today.
At the same time, we regularly hear some surprising news about groups of scientists claiming a break through in nuclear fusion with a completely new method. Especially great was the excitement 25years ago, when two chemists claimed to have achieved what they called “cold fusion” by electro chemical means. Briefly there was hope of accessing a practically in exhaustible source of energy. It was a hope that proved just as deceptive as the results of the underlying research.
In the last days we were able to read (on the back pages of news papers) another headline on nuclear fusion. The US defense company Lockheed Martin,so far not known as a leading research institute for plasma physics,reported with strong words and poses that“after four years of secret work”it succeeded in developing are volutionary new type of fusion reactor. A“radically new method“ enabled them to deal with the well-known and previously seemingly insurmountable problems of nuclear fusion technology. With strong language and colorful images the scientists make reference to the nearly infinite source of energy of our sun and thus proclaim the golden age after solving all our energy problems. It is hard to believe that the newcomers have suddenly found the solution to a problem which already two generations of physicists have struggled with. But of course we cannot rule this out.
The principle of a nuclear fusion power plant is quite simple in principle: One wants to produce energy exactly on the way as done in the sun. Since the 1930s physicists know that under very high pressure and temperature hydrogen nucleifuse into heliumnuclei. In this process enormousamounts of energy are released, much more than in the reverse process of nuclear fission which has been technically controlled for 50 years now. In practice, the controlled fusion of light atomic nuclei is not quite so simple(uncontrolled fusion has been technically applied since the 50s: it is the principle of hydrogen bombs). One inserts the hydrogen nuclei-more precisely, the isotopesdeuteriumandtritium–in avacuumvessel and then, with the help of microwaves,bring the gas to a very high temperature. This creates a so-called plasma, in which the atomsare freed from their electrons and are thuselectrically charged. The target temperature at which the desired fusion process occursisan unimaginable 100 million degrees.So far so goodandtechnicallystillrather easy to achieve. However, this plasma must now be kept in check, as it immediately cools in contact with the container walls, which in turn terminates the fusion. This purpose serve enormousmagnetic fields. To produce and maintain them is the real technological challenge on which top scientists around the worldhave worked for decades.So far,withmoremoderate success-but highfinancial cost. Nevertheless,physicistsarehopeful(you would have to think optimismisalmosta necessarytraitfor these characters). Currently an international consortiumis in the process of building the experimental reactor“Iter“ in Cadarache, France, which is expected to produce first results as of 2030. Earliestin 2040it isexpected to produce a considerable net amount of energy.
With a new arrangement of the magnets, the American military engineers now claim to have found a way to make the rector“ten times more efficient“ than in previous designs. It could thus be builtten times smaller providing the same performance, which would be an enormous breakthrough indeed.On closer inspection, however,two issues catch the experts’ eyes. First, the idea is by no means new. It runs under the name“magneticcusp“and has already been rejected in the 80s, because too many of the high-energy particle scan escape from the plasma, which creates a negative energy balance of the reactor. Secondly, the so“radically new“ arrangement of the magnets causes the plasma to cool down too quickly.
So we have every reason to be skeptical about this“new breakthrough”in nuclear fusion research. We have to wonderwhatLockheedintended.Isthis onlyalarge-scalemarketing gimmick? We should note that a lot of money is involved: Lock heed is looking for partners and thus financing. It would not be the first time that companies squint at the pot of public tax dollars. And this is a fair endeavor, as this technology, once up and running, would indeed represent a societal paradigm shift.Were we one day actually be able to produce energy in the same way as the sun, it would constitute not only a technological leap, but also acivilizational one, comparable only to the steam engine which 250years ago began to completely revamp our society.
Lockheed’s sales story stresses exactly this point. The fact that science now a days must also include a clever marketing was recently illustrated to us by the „Human Brain Project“. But that is a topicforan entire newblog.