Sun in a Bottle: The Strange History of Fusion and the Science of Wishful Thinking - Charles Seife (2008)
Chapter 4. KINKS, INSTABILITIES, AND BALONEY BOMBS
Among other bodies which the alchemists of the middle ages thought it possible to discover, and accordingly sought after, was a Universal Solvent, or Alkahest as they named it. This imaginary fluid was to possess the power of dissolving any substance, whatever its nature, and to reduce all kinds of matter to the liquid form. It does not seem to have occurred to these ingenious dreamers to consider, that what dissolved everything, could be preserved in nothing.
—GEORGE WILSON, RELIGIO CHEMICI
The sun itself needs no bottle. It is held together by its own gravity; the mutual attraction of all its atoms is able to keep the fusion engine in its belly from blowing itself apart. But any lump of material smaller than a star does not have enough gravitational force to counteract the enormous pressure of an expanding fusion reaction. For humans to succeed in making an earthbound sun, scientists would have to figure out how to contain the fusion reaction with an external force—figure out how to bottle it up.
The Teller-Ulam design used atom bombs to create a temporary bottle. Pressure from the radiation of a fission bomb squashed the fuel from the outside; pressure from the explosion of a fission “spark plug” compressed the fuel from the inside. Caught in between these two nuclear anvils, the deuterium and tritium fuel was crushed, heated, and bottled up for a fraction of a second. The result was a brief burst of fusion energy: an exploding sun. However, the brevity and violence of the explosion made it suitable only as a weapon of war. To harness the power of fusion for peaceful purposes, scientists needed a much subtler kind of bottle.
In the early 1950s, the need was growing urgent. In the past, the United States had always produced more energy than it needed, but that trend was rapidly changing. Economists and scientists knew that by the end of the 1950s, America would have to begin importing fuel—oil—to keep its economy going. In Britain, the situation was even worse; dependent on oil imports, the United Kingdom was embroiled in a spat with its main supplier, Iran.30 The West was getting its first taste of oil addiction, and it wasn’t pleasant. Fusion energy—if scientists could design a bottle to contain it—could prevent a future where the Western world was kept hostage to a dwindling and increasingly expensive supply of foreign oil.
On March 25, 1951, Argentina announced that it had designed such a bottle. Argentina’s scientists were claiming they had solved humanity’s energy problems. It was a few days before the Greenhouse tests, and Ivy Mike was months away. The United States had not yet liberated fusion energy, but Argentina’s president, Juan Perón, was gleefully bragging about having generated “thermonuclear reactions” and harnessing the power of the sun.
The New York Times reported the claim on page 1: “The project is still in the early stages, but when Argentina is able to produce as much energy as deemed necessary, all will be used solely for industry, President Perón declared.” Not only was Perón willing to forswear his bomb-making ambitions, but he couldn’t resist tweaking the scientists in the United States and the USSR who were trying to turn fusion energy into weapons. “Foreign scientists will be interested to learn that while working on the thermonuclear reactor, the problems associated with the so called hydrogen bomb were studied in great detail, and we have been shocked to find that results published by the most reputed experts are far removed from reality,” Perón told a gaggle of Spanish-language reporters who had been summoned to a press conference at the Argentine presidential palace.
For such a dramatic claim, Perón provided very few details. The reactor used “a totally new way of obtaining atomic energy”—fusion. Experiments had been under way for some time and had yielded some very promising results, bringing matter to temperatures of “several million degrees.” This success led Perón to establish a pilot fusion energy plant to create “artificial suns on earth.” This plant was on a small island in a lake near the Chilean border: Huemul Island.
The director of the Huemul reactor was a German-speaking scientist named Ronald Richter, of whom little was known. After Perón finished speaking, Richter addressed the Spanish-speaking reporters through a translator. “What the Americans get when they explode a Hydrogen bomb, we in Argentina achieve in the laboratory and under control,” Richter said. “As of today, we know of a totally new way of obtaining atomic energy which does not use materials hitherto thought indispensable.” At the press conference and in a follow-up one the following day—no foreign press allowed—Richter spoke of controlled explosions of lithium and hydrogen and deuterium. And he claimed that he had achieved fusion at his mysterious lab on Huemul Island: “Yes, sir, for the very first time a thermonuclear reaction has been produced in a reactor.”
The statement promptly set off a firestorm. Many in the physics community quickly rejected the claim; scientists around the world scoffed at Richter. When American reporters asked David Lilienthal whether there was the “slightest chance” that Argentina had attained fusion, he answered, “Less than that.” A Brazilian scientist noted that “It is strange that the names of eminent physicists working at present in Argentina are not associated with the announced atomic project.” And when asked what material other than hydrogen Richter could be fusing, a former Manhattan Project physicist, Ralph Lapp, was quick with an answer. “I know what that other material is that the Argentines are using,” he told Time magazine. “It’s baloney.” (Time promptly dubbed Richter’s reactor the “Baloney bomb.”)
Perón bristled at the criticism. “I am not interested in what the United States or any other country in the world thinks,” he snarled, lashing out at the foreign politicians and newspapers who “lie consciously” and spread deception. “They have not yet told the first truth, while I have not yet told the first lie.”31 And even as some scientists ridiculed Perón’s claims, others began to chime in, supporting Richter’s assertions. The mystery of Huemul Island, a drama that would last for months, was getting deeper by the day. It was just beginning.
Richter’s claims marked the official beginning of a quest that had been in the planning stages for a long time—the quest to liberate the energy of fusion for the benefit of mankind. Years before scientists achieved fusion on Earth, they had realized that the uncontrolled violence of hydrogen bombs was far from an ideal way to harness the sun’s power. What physicists really wanted was a fusion reaction they could control. They wanted a reactor that produced energy by fusing hydrogen into helium, and they wanted it to be stable, unlike the dangerous evanescent explosion of a fusion weapon. To create a workable reactor that would tap the unlimited potential of fusion energy, scientists needed to build a sun in a bottle.
Soon, scientists the world over were squabbling, alternately claiming triumphs and debunking them. The Huemul drama was the first act in the quest to create a tiny, controllable fusion reaction. But it was far from the last.
At first glance, it seems impossible to make a bottle sturdy enough to contain a burning sun. What kind of material is strong enough to hold a fusion reaction? To get even the most fusion-friendly atoms to stick to one another, they have to slam together hard enough to overcome their mutual electric repulsion, so the atoms have to be extraordinarily hot—tens or hundreds of million degrees Celsius.32 But matter at such high temperatures is very hard to contain. It is hotter than anything on Earth, far hotter than the melting point of steel. Even a diamond vessel would instantly evaporate in temperatures that extreme. Million-degree substances act almost like universal solvents, eating through whatever substance you put them in. Nothing on Earth would be able to contain such hot matter, at least not without some extraordinarily clever tricks.
Ronald Richter did not have the credentials one would expect of someone who could come up with such a clever trick. He didn’t have a terribly strong scientific background. As a student, he apparently had tried to study (nonexistent) “delta rays” coming from the earth, but his proposal was rejected by his professors. His adviser merely remembered him as a “so-so” student. He hadn’t published any scientific papers and had scant experience in the laboratory. But when Perón suddenly announced that Richter had created a sun in a bottle, he caught the world’s attention.
In the days after Perón’s announcement in March 1951, Richter provided a few more details about his reactor, which he called the “thermotron.” He described the device as a “solar reactor furnace” and said the reactor worked by fusing deuterium with lithium—a light metal whose atoms have three protons and three or so neutrons—at 10,000 degrees Fahrenheit. This was far short of the tens of millions of degrees that fusion scientists thought were required to initiate such a reaction. Richter also said that the reactions in the thermotron created little explosions, micro-fusion-bombs, which, however, were well-contained by large stone walls that surrounded the furnace. For most scientists, this announcement only increased their skepticism. But for others, Richter’s work began to seem plausible, and they started jockeying to share in the credit for the discovery.
On April 1, the New York Times announced that a French physicist supported Richter’s claims. The physicist was asserting that, a few months prior, he had performed experiments whose results bore a “striking similarity” to what the Argentine scientist was seeing. In the same issue, the Times’s science editor, Waldemar Kaempffert, wrote that “Richter admits that his process is not new,” and the journalist listed some of his intellectual forebears: the Britons John Cockcroft and Robert Atkinson; the German Fritz Houtermans; the Russian émigré George Gamow; and, of course, Edward Teller. Kaempffert conceded that Richter might have made a breakthrough, but he rejected Perón’s comment that everyone else was on the wrong track. “American and European scientists are fully aware of the work of Atkinson, Houtermans, Gamow, and Teller,” he sniffed. If Richter had made a breakthrough, it was not Argentina’s alone. It was due, in part, to the work of American, British, and German physicists.
Later that month, Perón pinned the Peronist loyalty medal on Richter’s chest, and in May he established a national physics laboratory to exploit the discovery. The Dutch government started negotiating nuclear research deals with Argentina. The South American country was trying to become a major player in nuclear politics. At the same time, though, the criticism and scorn from foreign skeptics became increasingly caustic. Time magazine and other outlets picked up a rumor that Richter had been arrested. A Brazilian newspaper, Time reported,
said that Dr. Ronald Richter, the former Austrian scientist, was arrested after technical experts of the Argentine army had discovered that Richter “was not sufficiently advanced as a physicist” to achieve the atomic release Perón had claimed. Three experts informed Perón that Richter, in their opinion, was nothing more than a “colossal bluff.”
It wasn’t true, but it amplified the claims of fraud that surrounded Richter. Also in May, the Austrian physicist Hans Thirring published an article that asked whether Richter’s scheme was “a swindle.” The answer consisted of the following possibilities:
a. Perón has fallen victim to a crank suffering from self-delusion 50%
b. Perón has been taken in by a sly swindler 40%
c. With the aid of Richter, Perón is attempting to bluff the world 9%
d. Richter’s assertions are true 1%
Richter lashed back the next month—in the paranoid and combative style of the professional crank. “The reactor operation crew and I are deeply sorry for Herr Thirring, because he revealed himself to be a typical text book professor with a strong scientific inferiority complex, probably supported by political hatred,” he wrote. And of the reports that he had been arrested in secret? “It must really have been the deepest degree of secrecy because I only know of it through the newspapers,” Richter sneered. “I am not impressed by these well-known methods of psychological warfare.” His research would continue unabated, and he would likely have a thermonuclear reactor “in full-scale operation in about ten months or so.”
The rumors of Richter’s arrest, at least, were false, and work continued at Huemul, apparently on schedule. In October, Richter announced that a large-scale experiment had been successful. By December, he was bragging that he “would be able to make convincing new demonstrations within three months.” The Associated Press reported Richter’s claim that he was in negotiations with a “highly industrialized foreign country” to trade his nuclear secrets for money and raw materials. He added that foreign skeptics “soon would have to eat their words.”
Instead, Richter was the one who would get his comeuppance. Three months later, he failed to produce his “convincing new demonstrations,” and he became the butt of jokes in Argentina. Detractors, seeing Richter in a café with a bandage on his hand, commented snidely that the good doctor had been wounded when one of his atomic bombs exploded in his hands. In the lab, Richter’s behavior was becoming increasingly bizarre. He requested pumps to inject gunpowder into the reactor. In April 1952, Pedro Iraolagoitia, a Peronist navy pilot, visited Huemul to inspect the plant. He was shocked when Richter deliberately blew up a tank of nitrogen and hydrogen, blowing the door to the lab clean off. Weirder still, right after he triggered the explosion, Richter scuttled over to his instruments and on a piece of paper spewed out by one piece of equipment, he wrote “atomic energy.” Iraolagoitia figured that Richter was insane. Soon he had convinced Perón to launch an investigation into the Huemul project, and a group of scientists and politicians visited the island in September 1952.
The visit was a fiasco. Richter showed the scientists his fusion reactions. In the reactor chamber, vivid red lithium and hydrogen flames spewed forth; the dials of the Geiger counters fluttered. The scientists weren’t impressed. Neither were the gamma-ray detectors that the physicists brought with them. Unlike Richter’s Geiger counters, the gamma-ray detectors showed no evidence of radiation whatsoever—radiation that had to be there if, indeed, fusion was occurring. Stranger still, when they exposed Richter’s equipment to a real source of radiation—a piece of radium—the counters didn’t chirp at all. The equipment had been rigged. The Geiger counters weren’t responding to radiation but to the electrical discharge that ignited the ersatz fusion reaction. At best, Richter was deluded. At worst, he was a fraud. Even Perón, Richter’s biggest backer, had to admit that Richter’s nuclear fusion was a farce.
The failed Huemul project quickly became an embarrassment for Perón. Richter began to face accusations from Argentina’s legislators, and in December, despite official denials, the Argentine dream of fusion energy was over. Rumors of Richter’s incarceration began to appear in the press, but in truth it was two more years before he was finally arrested.
Perhaps it was naïveté or optimism that drove him; perhaps it was greed. Perhaps it was the desire for power. Whatever the reasons for Richter’s bold claims, he had wasted millions of dollars’ worth of Perón’s money in his pursuit.33 If he had succeeded, Perón’s Argentina would have solved the world’s growing energy crisis overnight. Humanity would have considered Richter its savior.
Instead, Richter found himself accused of fraud, scorned and humiliated. He was just the first casualty of the quest to put the sun in a bottle.
Lyman Spitzer, a physics professor at Princeton University, was about to leave for a ski trip to Aspen in March 1951 when the papers broke the story about Richter’s fusion reactor. Spitzer was instantly incredulous, but at the same time he was intrigued. On the ski slopes, he wondered just how to make a device that could hold a miniature sun. By the end of his sojourn, Spitzer was well on his way to designing one. Instead of using nuclear weapons to contain fusing hydrogen, Spitzer would exploit the odd properties of extremely hot matter, properties of what physicists call a plasma.
Heating an object changes the way it behaves. A frozen hunk of water is solid ice. Put it on a table and it will retain its shape. Heat it a bit and the ice changes, melting into a liquid. Though liquid water still has a definite volume, it no longer has a fixed form; it will change its shape to fit whatever container you put it in. Heat it some more and the fluid changes again. The water boils into a gas: steam. As a gas, the formless cloud no longer even has a definite volume. A gas expands or contracts, depending on the pressure and temperature of its surroundings. As matter gets hotter and hotter—more and more energetic—its atoms’ random dancing speeds up and it eventually changes from solid to liquid to gas. This much scientists knew for centuries. Only at the end of the 1800s did physicists begin to realize that extremely hot gases changed their properties yet again. The reason has to do with the composite nature of the atom.
GAS VERSUS PLASMA: In a gas (left), every electron is stuck to an atom. In a plasma (right), the electrons roam free, attracted by nuclei, but not attached to any single nucleus.
As scientists realized at the beginning of the twentieth century, atoms are not quite as uncuttable as their name would imply. Protons and neutrons sit in the center of the atom, making up a small, dense, heavy, positively charged nucleus. Surrounding the nucleus are light, negatively charged electrons. Ordinarily, electrons are bound to a nucleus; the opposite charges of the protons and electrons attract each other, so the electrons cannot easily shake free. In fact, the nucleus and the electrons attract each other so strongly that the whole mess behaves very much like a single object.
Yet this isn’t always the case. Raise the temperature and the atoms start moving faster and faster. There’s a lot of energy about, and some of that energy winds up exciting the electrons. If the temperature is hot enough, the electrons get so excited, so pumped full of energy, that they can escape the bonds of their nuclei, and the atom loses an electron. As the temperature rises, the available energy increases, the electrons become more excited, and one by one they escape their bonds.34 Finally, at a high enough temperature, all the electrons are stripped from their nuclei.
The electrons are still nearby, unattached to any particular nucleus. Unbound electrons and nuclei roam in one big blob, unattached to each other. At extremely high temperatures a hunk of hot matter becomes an undifferentiated soup of unconnected negatively charged electrons and positively charged nuclei.
This is a plasma. Pour enough energy into a piece of matter—heat it enough—and atoms lose their individuality. The positively charged nuclei are still attracted to the negatively charged electrons, but they are not bound together. And this gives a plasma some unusual properties. Unlike most kinds of ordinary matter—unlike most solids, liquids, and gases—the free-floating electrons and protons of a plasma are strongly affected by electric and magnetic fields.
To Lyman Spitzer, this suggested a design of a bottle that could hold a miniature sun. Spitzer’s bottle would not be made of steel or stone or diamonds. It would not be made of any kind of material at all; after all, nothing would be able to stand up to the immense heat of a fusion reaction. Spitzer’s bottle would be made of invisible lines of force: it would be made of magnetic fields.
By the twentieth century, these fields were extremely well understood. Physicists had long been amazed by the intricate interplay of electric fields, charged particles, and magnetic fields, but in the nineteenth century, physicists figured out that these interactions are governed by only a handful of relatively simple rules. Nonetheless, even simple rules can have seemingly complicated consequences.
For example, the laws of electromagnetism dictate that moving charges are affected by magnetic fields, while stationary ones are not. It’s a quirky-sounding rule, but it’s what the equations dictate: if you put a stationary charged particle (like a proton) in a magnetic field, it won’t feel the field at all. A charged particle that is moving, on the other hand, is tugged and deflected by a magnetic field. More specifically, a moving charged particle feels a magnetic pull perpendicular to its motion. This force makes the particle change course. Instead of moving in a straight line, the particle moves in a circle, and the stronger the magnetic field, the tighter the circle. Conversely, the equations of electromagnetism dictate that a moving electric charge (like an electron moving down a wire) will generate a magnetic field. A stationary electric charge won’t. In mathematical terms, these are pretty simple rules to describe. But just these rules can give you a hint of how complicated a plasma must be.
In a plasma, you have a large number of charged particles—electrons and nuclei—moving about at relatively high speeds. These moving particles generate magnetic fields. These magnetic fields change the motion of the moving particles. When the motion of the moving particles change, so do the magnetic fields that they are generating—which changes the motion of the particles, changing the magnetic fields, and so on. Add to that the electric attraction that the electrons and nuclei feel for each other and you’ve got an incredibly complex soup.
Nevertheless, to Spitzer, the mere fact that the plasma responds to magnetic fields suggested a way to bottle it up. He realized that if you had a plasma moving through a tube and you subjected that tube to a nice, strong magnetic field in the proper orientation, the charged particles in the soup would be forced to move in little circles. They would spiral down the tube in tight little helices, confined by the magnetic field, never even getting close to the walls of the cylinder. The plasma would be confined. In theory, even an extremely hot plasma could be trapped in such a bottle. Furthermore, it was fairly easy to generate the right sort of magnetic field: just wrap a coil of wire around the tube and put a strong current through it; the moving charges in the wire create just the sort of field that is needed. It was a simple, but powerful, idea.
The only problem with Spitzer’s tube was that it bottles the plasma on the sides, but not at the front or the back of the tube. When the moving plasma reaches the end of the tube, it spills right out. So what to do? Spitzer’s next clever idea was to imagine a tube without end: a donut. Such a donut (or a torus, as physicists and mathematicians like to call it) is just a tube that circles back upon itself. The plasma would move around and around in a circle, never spilling out the end of the tube. With the right magnetic field, it would be a perfect bottle.
Unfortunately, the very curvature that gets rid of the end of the tube makes it very difficult to set up the right kind of magnetic field. The straight tube merely needed a wire curled around it. But when you bend that tube into a donut, the loops of wire on the inside of the donut get bunched up and those on the outside get stretched and spaced out. As current flows down the wire, the magnetic field is stronger where the loops of wire are close together—near the donut hole—and weaker at the edge where the loops are far apart. The nice, even magnetic field in the tube is destroyed; it becomes an uneven mess with a strong side and a weak side. This unevenness is a big problem: it causes the nuclei and electrons in the plasma to drift in opposite directions and into the walls of the container. The bottle quickly loses its contents. It leaks. A straight tube leaks out its ends; a curved tube leaks through its sides.
Even though a torus-shaped bottle would be leaky, Spitzer quickly came up with a design to minimize the leak. Instead of a simple donut, he reasoned, it would be better to have two half donuts. These half donuts would be connected by tubes that crossed each other: a figure eight. The half-donut sections have the same problem as the full-donut bottle: the electrons and nuclei drift in opposite directions. However, because the tubes cross each other, the plasma winds up going through one half donut clockwise and the other one counterclockwise. This means that the drift on one side should be cancelled by an equal and opposite drift when the plasma goes through the other half donut. It doesn’t quite work that way; the drifts don’t cancel exactly, and the plasma still leaks out a bit, but the leak isn’t quite as severe as it would be in a torus-shaped bottle.
The figure-eight bottle was a good enough design for Spitzer to begin experimenting. In July 1951—as the Huemul controversy continued raging in the press—Spitzer got a grant from the Atomic Energy Commission and set to work at Princeton, generating a serious design for a figure-eight-shaped fusion reactor: the Stellarator.
The Stellarator wasn’t the only fusion reactor in town. Shortly after the Livermore laboratory was founded, some of its scientists proposed a slightly different shape for a magnetic bottle. They would stick with a straight tube. Instead of wrestling with the problems caused by curving the plasma’s path, they would try to cap the ends of the tube by tweaking the magnetic fields slightly. Strong magnetic fields at the ends of the tube and slightly weaker magnetic fields at the center would create barriers that would behave almost like a mirror. Some—not all—of the plasma streaming to the end of the tube would be reflected back inside. This magnetic mirror was extremely porous, so it was clearly not a perfect bottle, but neither was the Stellarator. The Livermore scientists got down to work.
A third contender came from across the Atlantic. In the late 1940s, British scientists were also beginning to think about confining plasma, and their method relied on an entirely different phenomenon that they called the “pinch” effect.
A pinch starts with a cylinder of plasma. Since the electrons are free to move around inside the cloud, the plasma itself conducts electricity; it’s almost like a piece of copper. You can send an electric current along a plasma cylinder just as you would along a copper wire. And just as in a copper wire, the current running down the plasma creates a magnetic field. But this magnetic field affects the particles in the plasma; it forces them toward the center of the cylinder. The current compresses the cylinder, crushing it toward its central axis. The stronger the current, the greater the effect, and the faster and tighter the plasma gets squashed. As an added benefit, the squashing heats the plasma. This is the pinch effect.
British scientists immediately seized on this effect as a way to confine and heat a plasma until it begins to fuse. Several British laboratories began work on pinch projects, particularly Oxford University’s Clarendon, and neighboring Harwell, a few miles away. James Tuck, a physicist who had been involved with the Manhattan Project, worked briefly on the Clarendon fusion project before returning to Los Alamos, bringing the pinch idea with him.
To Tuck, the pinch method seemed an especially promising way to build a fusion reactor. If you could pump enough current into a plasma of deuterium and tritium, the plasma would heat and compress itself all in one fell swoop—perhaps enough to ignite fusion on a small scale. In 1951, Tuck asked for money to build a pinch machine, and in 1952 he built his first. In contrast to Spitzer’s hubristic name—Stellarator implied a mini-sun—Tuck called his instrument the Perhapsatron.
The Perhapsatron, the Stellarator, and the magnetic mirror all showed great promise. At least on paper, they were all able to contain a plasma in a magnetic bottle. Within a few months, scientists had come up with not one but three containers for an uncontainable substance. The Atomic Energy Commission decided to pursue them all. By the time Richter was finally unmasked as a fraud, the United States had consolidated these three efforts into one project: Project Sherwood.35
At first, Sherwood’s funding was modest, a few hundred thousand dollars or so per year. The budgets would not stay small for long. Though Project Sherwood was classified, it would soon hit the world stage. By mid-1955, rumors abounded that Britain, the USSR, and the United States were all trying to solve the world’s energy problems with fusion—and that U.S. scientists were about to build a prototype fusion reactor. In August, fusion scientists from around the globe met in Geneva for the first UN Conference on the Peaceful Uses of Atomic Energy. The conference president, the Indian physicist Homi J. Bhabha, stunned the world with a bold pronouncement. “I venture to predict that a method will be found for liberating fusion energy in a controlled manner within the next two decades,” he said. “When that happens, the energy problems of the world will truly have been solved forever, for the fuel will be as plentiful as the heavy hydrogen in the oceans.” The dream of fusion energy had been officially made public. Within twenty years, humanity would have limitless energy. The energy problems that had plagued civilization would be a thing of the past.
Lewis Strauss, the head of the AEC, was quick to claim a share of the dream. He confirmed that the United States was hard at work trying to build a reactor that would produce energy. The public and the press began to learn about Project Sherwood, if only the gross details. They knew nothing about the problems that were looming.
Fusion scientists started off very optimistic about their designs; on paper, the machines they were building seemed sure to work. In his 1951 proposal, Spitzer estimated his small Stellarator would generate about 150 million watts of power.36 The Perhapsatron looked even more promising. It was technically simpler and thus seemed likely to achieve fusion sooner. Once it did, it would be easy to turn a pinch-type device into a reactor. It could behave like a fusion-powered version of an internal-combustion engine: inject fuel, compress it with a current, ignite it, extract the energy, and get rid of the nuclear “ash.” It seemed almost too easy, and everybody was pursuing the idea. Despite the secrecy surrounding the early fusion reactor programs, U.S. scientists were certain the British and the Russians were working on pinch-type reactors.
The enthusiasm surrounding the technology, though, hid a lot of difficulties—and some infighting. Spitzer and the Princeton Stellarator team thought their idea was the path to fusion energy, and tried to tear down the Perhapsatron idea championed by their rival, Los Alamos’s Tuck. In fact, Spitzer spent some of his AEC grant trying to prove that a Perhapsatron would not work. It was money well spent. Two of his team members, Princeton professors Martin Schwarzschild and Martin Kruskal, found a very disturbing flaw that threatened to disrupt the Perhapsatron research program altogether. A pinched plasma was unstable.
Perhaps the easiest way to understand stability and instability is to imagine a ball sitting at the bottom of a hill. This is a stable system. Give the ball a slight nudge and it will roll right back to where it started. The system resists change; it won’t be ruined by small perturbations. A ball perched on the top of a steep hill, on the other hand, is in a precarious position. Give it even the slightest nudge and it will roll down the slope, abandoning its previous place. This system doesn’t resist change—indeed, even a tiny disturbance will change it dramatically. This is an unstable system.
Kruskal and Schwarzschild had discovered that a pinched plasma was like a ball perched on a hill. The slightest disturbance would destroy it. Send a current through a cylinder of plasma and it indeed squashes itself into a dense little filament of hot matter. But the filament is unstable. If it is not perfectly straight, if it has even the tiniest kink, the magnetic fields generated by the pinching current immediately exaggerate and expand the kink. This makes the kink grow, getting more and more pronounced. Any little imperfection in the plasma filament rapidly becomes a huge imperfection. In a tiny fraction of a second, the plasma kinks, bends, and writhes out of control.
As soon as the Perhapsatron started up in 1953, the Princeton team’s calculations were proved correct. The Los Alamos experimenters found that as soon as they got a pinch, forming a nice, tight filament in the center of the Perhapsatron’s chamber, it went poof! The pinch would disappear, setting the whole chamber aglow. High-speed cameras revealed the filament buckling and writhing, quickly striking the walls of the chamber. The kink instability had claimed its first victim. The Perhapsatron, as built, was incapable of fusing anything at all. The Los Alamos scientists needed to figure out how to stabilize the filament if they were to progress. They tried using an external magnetic field to “stiffen” the plasma filament somewhat, but the essential instability remained. Pinches were in trouble.
KINK INSTABILITY: If a pinching plasma has even a tiny kink in it, that kink will grow; the plasma will writhe out of control and hit the walls of its container.
Soon, the other designs were as well. In 1954, Edward Teller figured out that a plasma held in place by magnetic fields was unstable under certain conditions. The magnetic fields behave somewhat like a collection of rubber bands: as the plasma pressure increases, they try to relieve the increasing tension by writhing. “They try to snap inward and let the plasma leak out between them,” Teller wrote. This system was also unstable. Even a tiny irregularity in the magnetic field would rapidly get worse, and scientists would lose control of the plasma. The so-called Teller instability affected the Stellarator as well as Livermore’s magnetic mirror approach. Instabilities were everywhere.
By the mid-1950s, all three groups had enormous difficulties to overcome. Their plasmas were unstable and their bottles were leaky. They spent ever-increasing amounts of money building bigger and more elaborate machines in attempts to get unstable plasmas under control. The few hundred thousand dollars spent on magnetic fusion in the early 1950s turned into nearly $5 million by 1955 and more than $10 million by 1957. Plans for reactors also got more ambitious: by 1954, Spitzer was suggesting that $200 million would buy a machine that would produce thousands of megawatts of power—bigger than the biggest power plants around.
Despite Spitzer’s bold plans, Teller’s Livermore got the largest share of funding, about half of the Project Sherwood money. Princeton came in second, and Los Alamos, with its pinch program, was a distant third. Yet it was Los Alamos that first claimed victory.
By the beginning of 1955—just before Bhabha’s speech at the UN conference brought worldwide attention to the promise of fusion energy—the Los Alamos researchers saw indications that their plasma was hot enough to fuse deuterium. Every time they initiated a strong, fast pinch in their latest machine, the scientists saw a burst of tens of thousands of neutrons. This was very encouraging, because neutrons are the best indicator of a fusion reaction.
Everyone in the fusion community was hoping to achieve two main kinds of thermonuclear fusion in a reactor. The easier kind used a mixed fuel: deuterium and tritium. When a deuterium (a proton and a neutron) and a tritium (a proton and two neutrons) strike each other hard enough, they fuse, creating helium-4 (two protons and two neutrons). The remaining neutron flies off with a great deal of energy. So in a successful deuterium-tritium reaction, the products will be helium-4 and neutrons. Deuterium-deuterium reactions are a little more complicated; there are two ways this kind of fusion reaction tends to happen. As the two deuterium nuclei collide and stick, either a proton flies off (leaving behind a tritium nucleus) or a neutron flies off (leaving behind a helium-3 nucleus). These two branches of the reaction are roughly equally probable. Thus, if a reactor succeeds in fusing deuterium fuel, then the products will be helium-3, tritium, protons, and neutrons. Neutrons are produced by both deuterium-tritium and deuterium-deuterium fusion reactions. A burst of fusion—no matter whether the fuel is pure deuterium or deuterium mixed with tritium—will be accompanied by a corresponding burst of energetic neutrons.37
FUSION REACTIONS: (a) Two deuteriums collide and produce either a tritium and a proton or a helium-3 and a neutron. (b) A deuterium strikes a tritium and produces a helium-4 and a neutron.
Despite the problem with the kink instabilities, Los Alamos scientists were optimistic. If they could make the pinch strong enough and fast enough, they thought, they could get fusion going before the kink instability destroyed the pinch. In fact, Tuck’s calculations showed that such a machine could achieve breakeven—the fusion reaction in the machine would produce energy equal to what was needed to get the reaction going in the first place. (A fusion reactor that absorbs more energy than it produces is of no use to anyone.) And, Tuck argued, a larger machine could produce explosions equivalent to several tons of TNT per pinch. These explosions could be turned into usable energy, just as an internal combustion engine makes little fuel-air explosions turn a crank. Tuck built successively bigger pinch machines that could pinch the plasma harder and faster, and eagerly awaited neutrons produced by thermonuclear fusion.
When, early in 1955, the Los Alamos researchers turned on their newest, biggest pinch machine, Columbus I, they saw a burst of neutrons every time they pinched the plasma hard enough. Pinch. Neutrons. Pinch. Neutrons. No pinch, no neutrons. It seemed like a great success. From the number of neutrons they were seeing, the pinch scientists concluded they had attained fusion; the plasma inside the Columbus machine must have been heated to millions of degrees Celsius. But not everybody was convinced. Researchers at Livermore were skeptical that the pinch machine could reach the temperatures advertised. Thus, the plasma couldn’t possibly be hot enough to ignite a fusion reaction. So where were the neutrons coming from?
The Los Alamos physicists started making careful measurements on their pinch machine to see if they could pin down the origin of those neutrons. To their chagrin, they soon discovered that the neutrons coming out the front of the Columbus machine were more energetic than the ones coming out the rear. In a true thermonuclear reaction, during which nuclei in a hot plasma are fusing with one another, the neutrons from the reaction should be streaming out in all directions with equal energy. This was not the case with Columbus, so, clearly, the Columbus neutrons weren’t coming from thermonuclear fusion. They were coming from somewhere else.
The asymmetry provided a crucial clue. The scientists pinched the plasma by running a current through it. Neutrons that were flying out of the machine in the direction of the current had more energy than those that flew out against it. This revealed that the neutrons were the work of another instability. Just as a pinched filament is unstable when kinked slightly—because the kink grows and grows—it is unstable when a small section gets pinched a little bit more than the rest of the plasma. In this case, the small pinch grows progressively more pronounced; the plasma gets wasp-waisted and pinches itself off. The plasma begins to look like a pair of sausages. This is a sausage instability, and it creates some strong electrical fields near the pinch point. These fields accelerate a small handful of nuclei in the direction of the pinch current. These nuclei then strike the relatively chilly cloud of plasma and fuse, releasing neutrons.
From fusion scientists’ point of view, this kind of fusion was worthless. Scientists were hoping to get a hot cloud of nuclei fusing with itself, a thermonuclear fusion reaction. Instead, Columbus had made a small handful of very hot nuclei interact with cooler ones. This was roughly equivalent to shooting nuclei at a stationary target, and doing that, scientists had concluded, would always consume more energy than it produced. The neutrons produced by the instability, dubbed instability neutrons or false neutrons, weren’t a sign of energy production—just the opposite. Columbus’s neutrons were the sign of energy consumption, not energy production. The false neutrons had given the Los Alamos scientists false hope. Even so, the pinch technique still seemed within striking distance of igniting fusion.
SAUSAGE INSTABILITY: If a pinching plasma is slightly narrower in one place, that narrowing will get more and more severe and eventually squeeze the plasma to make it look like a pair of sausages.
By this time, the Americans knew they had competition from both the Russians and the British. Project Sherwood poured increasing amounts of money into ever-larger machines of all types. The most expensive one in the Sherwood portfolio was the model-C Stellarator proposed by Spitzer, which would cost roughly $16 million to design and build. So it was a humiliation when it appeared that the British had won the fusion race with a much smaller and less-expensive machine: ZETA.
ZETA, which had cost less than $1 million to build, was a powerful pinch machine. Its name reflected the optimism of its designers; ZETA was an acronym for Zero-Energy Thermonuclear Assembly, thermonuclear because it would achieve fusion and zero-energy because it would produce as much energy as it consumed. It was a very bold claim.
ZETA began operation in mid-August 1957 at the Harwell laboratory near Oxford. It wasn’t long before the machine made a big splash. Late in the evening of August 30, the ZETA device started producing neutrons. The scientists did hasty checks to make sure there wasn’t an equipment failure of any sort; the neutrons were real. Pinch. Neutrons. Pinch. Neutrons. Like their American counterparts before them, the British physicists thought the neutrons were the signature of fusion; after all, neutrons were the smoking gun that everybody had been seeking for so long. There were a few skeptics on the ZETA team—some doubted that ZETA had actually achieved fusion—but the joyful chorus of self-congratulation drowned out the voices of doubt. The mood was jubilant. Most of the ZETA team thought they had finally done it; they had built the first, rudimentary, artificial sun. The physicists present popped open a bunch of beers to celebrate.38
After weighing the evidence and crunching the numbers, the physicists at Harwell concluded that the plasma in the ZETA machine was reaching a temperature of five million degrees with every pinch, creating thermonuclear reactions and producing neutrons. If so, this was big news. It would be the first time that scientists had achieved fusion in a controlled environment. The British team naturally wanted to release their initial results right away, revealing the brilliant future of limitless energy to the public. But the Americans balked.
Earlier in the year, the British and Americans had decided to share data on fusion reactors with each other, and they were to decide jointly when and how to declassify the data and release it to the public. This last point became a source of contention. The Americans were reluctant to make an announcement about ZETA, in part because Project Sherwood had no signal achievements to brag about at the time. It looked as though the Brits had beaten the pants off the Yanks, so the Yanks needed some time to catch up. Thus, citing security issues, the United States tried to delay the announcement for a year. A second United Nations conference was scheduled for 1958, and what better place was there, U.S. officials argued, to release the results?
The British were unhappy about the American insistence on secrecy, and it is hard to keep a secret if one party wants to reveal it. Naturally, the secret didn’t stay secret for very long. By early September, news of ZETA’s success was leaking out. The English press was buzzing with rumors of successful nuclear fusion in the ZETA machine. By October, British scientists—including the Nobel laureate and Harwell lab head, John Cockcroft—hinted at encouraging results from the device. However, in deference to the Americans, nobody made an official pronouncement.
Hints about ZETA’s success got harder and harder to ignore. In November, a spokesperson for the British Atomic Energy Authority (BAEA) stated, “The indications are that fusion has been achieved” at ZETA, but gave no further details. English scientists briefed the House of Commons on their achievement. But the weeks ticked away without any description of what, exactly, had happened at Harwell.
The mystery deepened in December. Even as the BAEA denied that the United States was deliberately “gagging” ZETA scientists, preventing them from releasing their results, a BAEA spokesman admitted that Britain was awaiting American approval to publish the details of the Harwell experiment. The British press was infuriated and accused the United States of playing politics with a crucial scientific achievement, of needlessly delaying publication of an important experimental result. The British had beaten the Americans at their own game, and Lewis Strauss and the Project Sherwood crew seemed to be holding up the declassification process to give themselves time to catch up to the Brits.39
To the ZETA scientists, it was more than merely frustrating. Without a publication, it was as if the experiment had never happened. In science, publication is everything; without it, an experiment is worthless. It is easy for anybody to make an outrageous scientific-sounding claim. If you use the right buzzwords, you can make it extremely convincing; you can easily make the public believe that your claim is true. That’s what happened with Ronald Richter. Given a platform by Juan Perón, Richter trumpeted a remarkable achievement—based on pseudoscience—around the globe. Important people, including Perón, believed him. But very few scientists did. That is because Richter did not publish any scientific data that would have allowed specialists to verify his claim. To a scientist, an experiment is not believable without the precise details of how it was run and what the researchers involved observed. Only when scientists reveal the inner workings of an experiment to the world can their peers scrutinize the work and confirm or refute it. Only then will they be taken seriously. By blocking the publication of the ZETA results, the Americans were denying the British their chance at scientific glory.
Finally, the Americans succumbed to the pressure and gave Britain the go-ahead to publish the ZETA findings. When the Harwell scientists announced, in mid-January, that they were publishing their results in Nature at the end of the month, the British press was ecstatic. When they learned that the ZETA papers were to be accompanied by papers about Project Sherwood’s pinch project, the press was absolutely livid. It looked as if Lewis Strauss and the Americans, with their expensive machines, were trying to steal some of the Harwell laboratory’s glory. “Admiral Strauss’ tactics have soured what should be an exciting announcement of scientific progress so that it has become a sordid episode of prestige politics,” blared the British Sunday Observer. Despite the hurt feelings, everyone was relieved that the long wait was about to end.
When the Nature papers finally came out on January 24, the British and American scientists held a joint press conference. John Cockcroft announced that it was “90% certain” that ZETA’s neutrons had come from fusion, and outlined a twenty-year research plan that would lead to fusion reactors. The Americans presented their results, too, but they weren’t nearly as striking as ZETA’s. The press in the United States spun the story as a great British-American achievement. “Gains in Harnessing Power of H-Bomb Reported Jointly by U.S. and Britain,” the New York Times declared; “Nations Called Equal—Many Questions to Be Resolved.” America’s Columbus II machine was given pride of place above Britain’s ZETA, and the newspaper emphasized that the two nations were “neck and neck.” However, the rest of the world’s press ignored the American research and celebrated Britain’s triumphant conquest of fusion energy. In England, tabloid papers blasted the news across their pages, promising “UNLIMITED POWER from SEA WATER”: no more electricity bills, no more smog, no need for coal, power that would last for a billion years. Newspapers around the globe followed suit; they were quick to trumpet the prospect of limitless energy, energy that would be at humanity’s fingertips within two decades. No longer would any nation be held hostage because of a lack of oil. Even the Soviets congratulated the British—pointedly ignoring the Americans—on their “achievement in harnessing thermonuclear energy” and expressed their “admiration.”40 ZETA seemed to have begun a new era of humanity, the era of unlimited fusion energy, and it was the envy of the world.
Other nations began to emulate the British. The Swedes announced that they were building a ZETA-like device that could compete with the one at Harwell. Just two weeks after the announcement, Japanese scientists announced that they, too, had achieved thermonuclear fusion—and they were producing more neutrons than the British were. The Russians also started building a ZETA clone. But the Britons weren’t going to fall behind: by early May, they were busy upgrading ZETA and were planning a more powerful (and more expensive, at $14 million) machine, ZETA II. Its designers thought that ZETA II would heat plasmas to one hundred million degrees and produce more energy than it consumed. It would be the world’s first fusion power plant. On May 7, the New York Times optimistically reported on the characteristics of the new machine: “Britain Indicates Reactor Advance” read the headline. The following week, though, the paper planned a much less adulatory article: “H-Bomb Untamed, Britain Admits.” The dream had come crashing down. Once again, the culprit was those damn false neutrons.
Even while the ZETA scientists were cracking open beers, toasting their first fusion reactions, Basil Rose, a physicist at Harwell, was consumed by skepticism. He was unconvinced that the ZETA neutrons were truly from thermonuclear fusion. While Cockcroft and others plotted their twenty-year path to fusion energy, Rose racked his brain for a way to allay his doubts. He simply had to come up with a way of proving that the neutrons were coming from fusion and not from a bizarre instability.
The method he came up with was analogous to what the Columbus scientists had done several years before: he would look at the symmetry of the system. Rose ran the ZETA machine twice, once in its normal operating mode and once with magnetic fields and currents reversed. If the neutrons were coming from a true thermonuclear reaction, the neutrons would have the same energies, no matter whether the machine was running normally or in reverse. The reaction should be symmetrical. It wasn’t. The neutrons generated by normal ZETA had energies different from those produced by reverse ZETA. The neutrons weren’t coming from thermonuclear fusion. They, too, were false neutrons.
As soon as Rose published his results in Nature—on June 14, a month after Britain revealed its plans for the ZETA II—it became obvious that scientists at the Harwell lab had deceived themselves. John Cockcroft immediately regretted his “90% certain” remark and assured the public that ZETA was a success even though it hadn’t achieved thermonuclear fusion. “It is doing exactly the job we expected it would do and is functioning exactly the way we hoped it would,” he sheepishly explained. However, the damage had been done.
Like Richter before them, the British had gotten burned for crying fusion. Driven by their optimism and goaded by their egotistical desire for glory, the ZETA scientists had humiliated themselves in front of the world. The stakes of fusion energy were so high—virtually unlimited power to the nation that controlled it—that scientists couldn’t resist staking an early claim in achieving that lofty goal.
ZETA was a public relations disaster. For years, the cloud of ZETA hung over fusion scientists all over the world. In America, Project Sherwood physicists, despite their relief at not losing the race to the Brits, were despondent about what had happened. Fusion scientists were beginning to realize that fusion energy would be much more difficult to harness than they had thought. Fast pinches were not enough. There was no easy road to building a power plant with a magnetic bottle.
Even as scientists learned more about fusion, the dream of unlimited power seemed to slip further away. Another contender, though, was on the horizon, another way to confine a plasma and initiate a fusion reaction that would ignite another race for fusion energy.