192 Lasers Deliver a Nuclear Fusion Breakthrough
An incredible breakthrough happened last week that took me back to my early fascination (and education) in theoretical physics.
It revolves around the most famous physics formula ever written: E=mc2.
As Einstein posited in his now famous 1905 paper, “Does the Inertia of an Object Depend upon Its Energy Content?” energy and mass are different forms of the same thing.
It was the cornerstone of his special theory of relativity. And, as they say, the rest is history.
Just below the surface, however, there was another startling realization.
If the formula is correct, as one approaches the speed of light, something remarkable happens: The potential for almost endless energy emerges.
This is the driving force behind nuclear fusion. It’s an attempt to harness the awesome forces that power the sun and the stars.
If mastered, it could one day give the world a source of cheap and boundless energy. But the road to the inexhaustible sources of energy found in Isaac Asimov novels has been a long one.
However, now scientists believe they are on their way to overcoming one of its biggest barriers.
It involves 192 high-powered lasers…
A Massive Breakthrough at the National Ignition Facility
But first, let’s take a look at how this nuclear fusion works and the hurdle scientists have been working to clear.
As Einstein’s formula posits, energy and mass are related. Simply put, if you remove one from a system and the other is lost as well.
But under controlled conditions, this could result in a significant release of captured energy for each unit of mass. In fact, a number of experiments have confirmed Einstein’s “relativity” of mass and energy.
Since one gram of mass is equivalent to 85.2 billion BTUs, harnessing the process of fusing a nuclear mass and that gram would produce the equivalent of 21,500 tons of TNT or 568,000 gallons of gasoline.
That’s one single gram… and keep in mind that there are more than 28 of these guys in a single ounce.
However, the problem has been always been to come up with a way of initiating the fusion reaction that used less energy than was subsequently released.
After all, if you can’t create a net-positive in the energy column, all you have done is create is a neat (although expensive) party trick. Several attempts at nuclear fusion have fallen into this category.
However, word emerged late last Wednesday that scientists at the National Ignition Facility (NIF) at the Laurence Livermore National Laboratory in California had finally overcome this problem.
For the first time ever, a team led by Livermore physicist Omar Hurricane (a great name for an energy scientist), was able to generate more energy than was absorbed in a fusion reaction.
The breakthrough centered around 192 high-powered lasers contained in a 10-story building the size of three football fields.
The high-tech complex successfully heated and compressed a small pellet of fuel to a point that fusion reactions occurred.
Of course, this news does not mean you should race out and buy a fusion-based investment shares anytime soon. There are still a number of other hurdles to overcome before there is anything of genuine commercial value here.
But if this proves a real breakthrough, I can promise you a new rush of interest in nuclear fusion will result.
And the initial results are intriguing to say the least. An abstract of the experiment published in Nature can be found by clicking here.
Is This the Answer to Over 60 Years of Research?
Meanwhile, the announcement has started another round of energetic (no pun intended) discussions among those who for some time have championed fusion reactors as the future for energy. In fact, this debate goes back more than 60 years.
That’s how long proponents have been designing experiments that used more energy than produced… until last Wednesday.
For its supporters, nuclear fusion offers the possibility of an almost limitless source of energy without the dangers of nuclear fission – one of the world’s most controversial sources of power.
In this regard, fusion differs in several fundamental respects.
A fission reaction, the kind used in current electricity generation, produces energy by splitting atoms. Fusion, on the other hand, produces energy by molding two light atoms together into a heavier one, creating energy in a process revealed by Einstein’s formula.
And it would do so without creating any of the radiation concerns whatsoever.
But igniting the reactions has always remained the problem. The amount of energy needed to start the reaction had always exceeded the total amount of energy generated in a millisecond pulse. So there was no practical advantage until the ignition problem could be solved. That’s where last week’s experiment differed from earlier attempts.
What’s more, this approach has been successful several times since fall 2013.
As anybody who has struggled through a laboratory science course can attest, you need to replicate an experimental result under controlled conditions and receive the same results several times before you can conclude you have anything.
It’s Ever So Close… But Not Quite There
Yet, as the online version of Scientific American reminded shortly after last week’s paper was made public:
Scientists remain a long way from what’s known as ignition: the point at which fusion of any kind releases more energy than was consumed to start it. And the method used to produce this result is unlikely to create the conditions needed to reach that goal. “By lowering the compressibility, they have lowered the pressure that can be reached,” explains physicist Mark Herrmann, director of the Pulsed Power Sciences Center at Sandia National Laboratories, who wrote a commentary accompanying the research paper in Nature.
But the discovery team has also seen for the first time the early stages of the kind of physical processes needed to create such fusion. Specifically, the fuel showed evidence of what fusion physicists like to call “bootstrapping.” Essentially, the helium nuclei (otherwise known as alpha particles) thrown off by the fusing hydrogen isotopes left their energy behind, maintaining the conditions needed for yet more fusion. That helped more than double the superheating of the fusing fuel and suggests the team is halfway to the kinds of energies needed to achieve ignition. “As we pushed it in experiments, the bootstrapping kicks in more and more,” Hurricane says. “Seeing that kick is quite exciting and does show there is progress.”
So the “bootstrap,” while exciting, is not yet ignition. Nonetheless, this is the first time it has been accomplished.
To be realistic, this experiment is not something you are likely to reproduce in the garage. The entire apparatus, including the 192 calibrated lasers, cost around $3.6 billion.
But the next stage in this race will now be quicker. And as the process is refined, so will its applications.
So you see, thanks to that famous equation, there really is a basis for science “fiction.”
Warp drive, anyone?