The Soul of the Matter (4 page)

Chapter 10

A
ssembled in front of Viktor were eighteen high school students and their teacher, Mr. Reilly. They were in the center's media room, which was designed expressly for activities like tours and information sessions. Its walls were covered with colorful posters about fusion. On a table in the center of the room was a cutaway mock-up of the Alcator-E reactor. Off to the side was another table supporting a long, glass tube with electrodes at each end.

“I'm Dr. Weisman, and I'm pleased to be your guide this morning. I hope when you leave here, you'll have a good understanding of the importance, principles, and challenges of fusion energy,” Viktor said. He looked around at the students. “I'd like to begin by having one of you explain the difference between fusion and fission energy. And I have to caution you, I pick people at random if no one volunteers to answer a question.”

A tall, thin boy wearing a button-down shirt, navy-blue dress pants, and polished black shoes raised his hand. Viktor nodded and the boy answered, “Fission is when a larger atom is split into smaller atoms. Fusion is when smaller atoms are joined together to produce a larger atom. Both release large amounts of energy, though fusion produces much more and is what fuels our sun.”

“Good, your answer indicates that you are in the right place. Next question. Why does fusion energy matter?”

This time a girl in skinny jeans and a fashionable shirt responded, “Fusion can produce enormous amounts of energy without generating a lot of dangerous radioactive waste, and there is an almost unlimited supply of fuel.”

“Right. So why don't we have fusion power plants today? Why do we need a research facility such as this?”

This time a number of students raised their hands. The girl Viktor picked said, “You need extremely high temperatures and pressures and a way to generate power from that. No one's figured out how to do that yet.”

“Mostly correct. I see Mr. Reilly has prepared you very well. As you pointed out, the difficulties in building a fusion energy plant are significant. First, we have to create the conditions necessary for fusion to occur, in a controlled manner. Second, we have to get more energy out than was used to generate the fusion. Third, we need to build a plant that can capture that energy to generate electricity. Each of these is tough, and, as much progress as we've made, there is still a long way to go. Now please turn around and face the poster with the sun on it. Can anyone tell me the conditions under which fusion takes place in the sun?”

This time, only one student raised his hand. He answered, “Fusion takes place in the core of the sun, under intense gravitational pressure, where the temperature is about fifteen million degrees Celsius.”

Viktor nodded with a small smile. “Of course, we can't create pressure as intense as the core of the sun. So we need higher temperatures, in the range of one hundred million degrees. The ­Alcator-E is the experimental fusion reactor that does that for us.” Pointing to the cutout model on the nearby table, he added, “As you can see, it is a doughnut-shaped device. Powerful, hollow magnets form a ring. Inside, magnetic fields follow the shape of the doughnut and keep the fuel in place as it is superheated and compressed. Let me show you an example of using magnets to shape a field.”

Viktor pointed at the glass tube in the room and turned on a switch. “Inside this tube is ionized gas. High energy causes electrons to separate from the atoms' nuclei, thereby creating plasma, the fourth state of matter. The plasma in here is glowing pink and runs in a line, in the center of the tube, from end to end. Because the plasma consists of charged particles, we can shape it using a magnetic field.” As he said this, he picked up a fist-sized magnet and pulled it along
the bottom of the tube. Wherever the magnet was, the glowing plasma dipped down. He flipped the magnet over, thereby reversing the charge against the glass tube, and the plasma moved away from it. “In the Alcator reactor, we use the same principle to shape and compress the plasma.”

He then gave the magnet to the students and let them play with it, watching as they tried to create interesting shapes and effects.

As they took turns with the magnet, he asked, “Why do we need such high pressures and temperatures to fuse atoms?”

A student answered, “To overcome the electromagnetic repulsion of two positively charged particles.”

“You are a well-informed group of high school students.”

The student smiled and then looked at Mr. Reilly.

“We spent yesterday's class preparing. We appreciate the time you are giving us and wanted to get the most out of the tour,” Mr. Reilly said.

Looking at the room, Viktor said, “Very good. Then let's dispense with the simpler questions and get to more interesting ones. Once fused, why do the particles stay together?”

This time, no one rushed to answer.

Viktor said, “In the interest of time, I'll answer that. There are four fundamental forces in the universe: gravitational, electromagnetic, strong nuclear, and weak nuclear. The strong force binds particles in atomic nuclei together. It's only effective at small distances, basically the width of the nucleus of an atom, while the electromagnetic force retains its strength over very long distances. Once a force sufficient to overcome the electromagnetic repulsion has pushed two positively charged protons close enough together, they bind and release large amounts of energy. This shows the importance of how the ratio of the fundamental forces of physics determines all the behavior in the universe, even yours and mine. Now, what if the ratio of forces was just the least bit different, even less than a billionth of a billionth?”

“There would no universe at all,” replied the student who had provided the last answer.

“That's right. Pretty remarkable, and fortunate, that the forces just happen to be what they need to be for us to exist.”

A quiet, serious-looking boy asked, “Why are they that way? Could they someday change?”

Viktor knew this discussion could turn in the wrong direction rather quickly. He'd had many discussions with people who claimed that a creator “tuned and maintains” the forces so that life could form and exist specifically on earth, and he was determined to avoid the controversial topic. In reply, he said, “Quantum physics supports the existence of an infinite number of multiverses where, in aggregate, anything that can happen, does happen, somewhere. Accordingly, there is a universe capable of supporting our existence and we're in it.”

The boy crossed his arms. “So you're saying that every time anyone, anywhere, makes a decision or does anything, a whole new universe, with all the matter and energy and history of this one, instantaneously springs into existence out of nothingness into dimensions that we can't perceive, a multitude of big bangs bigger than the first big bang, and that the new universes don't interact with any other universe?”

Flustered, Viktor's face tightened. “I just stated one of the more generally recognized theories. In time, it may be disproved or replaced by another theory that better suits the data. But for now, many believe this best explains our universe.”

Mr. Reilly jumped in. “Ted is something of a science prodigy and has read up on quantum physics. A little bit of knowledge can be dangerous.”

“That's all right. Questioning is healthy,” Viktor said through tight lips.

With a look that hinted at sarcasm, the boy said, “It would be cool if multiverses were true. Every time I'd do or not do anything, my thoughts would cause the creation of a whole new universe in which another me, with the exact same history and mind as me, would have decided to do a different thing. I'd be more powerful than God, since He only created the universe once and I get to do it over and over again.”

Viktor didn't answer, so the boy continued. “And this would be happening with everyone, at all times. Not only that, but it took God six days and took so much out of Him that He had to rest a whole day and I do it instantly and feel like nothing happened.”

Another boy, with a muscular build and Patriots football jersey, teased, “Come on Ted. You can't even get Alyssa to go to the prom with you, and you think your thoughts create an infinite number of invisible universes?”

Ted replied, “The good news is that in a very large number of them, she actually said yes. Too bad she didn't in this one.”

An embarrassed girl who Viktor assumed was Alyssa said, “You asked better in the other universes.” Several girls stifled laughs.

As Ted's mouth flew open to reply, Mr. Reilly said in a strong voice, “Cut it out, or I'll make sure no one goes to any prom, in any universe.”

After everyone had quieted down, Viktor said, “All kidding aside, there is a lot we still need to find out. That's the fun thing about physics. There is always something new to learn. Now, let's go see what you came for.”

Everyone followed Viktor down the hall and formed a small circle by the door to the reactor room.

Viktor began, “As you may have noticed, these concrete doors are two feet thick. They shield us from the lethal neutrons generated by the reactor. Inside the large gray foam cylinder in front of you is the Alcator-E reactor. It has superconducting magnets that produce magnetic fields two hundred thousand times stronger than Earth's. Over there are radio frequency generators where radio waves, a thousand times stronger than a radio station's, are used to heat the plasma. When we run experiments, which we call ‘shots,' we heat and compress the plasma intensely for up to thirty seconds. During that period, we use as much power as the entire city of Cambridge. Of course, you can't just get that all at once from the power lines, so we build up a charge, store it in a huge flywheel, and then release it when it's needed. Before we head over to the control room, are there any questions?”

Instantly, a half dozen hands went up. Working left to right, Viktor picked one.

“What do you fuel this with?”

“Great question, and something I should have already mentioned,” Viktor answered. “We use a form of hydrogen called deuterium. It has two neutrons instead of the usual one, hence the ‘deu' in its name. An actual power-generating reactor would use a hydrogen mix that included tritium, which, as its name implies, has yet one more neutron. We don't use tritium here because we don't need to; it's hard to handle, and it's mildly radioactive, although it's only toxic if inhaled, and it's use is highly restricted.”

“Can the reactor explode or go critical?”

“Not in any sense of a nuclear explosion. There isn't enough fuel and you can't get runaway reactions. The worst that happens is the magnetic field fails and superheated fuel hits the walls and damages them.” Viktor pointed at the reactor and said, “Plus, with this, the hottest we get is seventy-five million degrees Celsius. For significant amounts of fusion, you need two hundred million degrees for a deuterium-to-deuterium reaction and one hundred million for a deuterium-to-tritium reaction.”

“What happens if something does go wrong?” one student asked.

“The worst case is you can get a beam of runaway electrons that could burn through solid steel. To prevent that, we have an extinguisher that releases argon gas into the vessel if there's a problem. This would convert the energy of the electrons into photons. The resulting light would be briefly brighter than a billion lightbulbs, or the brightest beam of light that's ever existed.” Pausing to let the idea sink in, Viktor then said, “Now let's head into the control room.”

After entering the room, Viktor faced the tour group and said, “The actual shots follow a procedure a lot like a space launch, with people sitting at monitors as a recorded voice counts down. While the shot is underway, we can see computer-generated images of the plasma and readings. Before you know it, the shot is over, and you're getting ready for another one. Pretty impressive, isn't it? Before I conclude the tour, are there any final questions?”

One student asked, “How do you measure the plasma temperature?”

“Another good question. Obviously, there aren't any physical probes that could withstand the heat. What we do is bounce laser beams off the plasma. While this is an accurate enough technique, it takes time for the computers to process the data and give us a reading.”

Mr. Reilly, stepped forward. “How far away are we from fusion energy?”

Victor sighed. “Decades. A consortium is building a prototype reactor in France called ITER. It was supposed to take ten years, but it's already been delayed. After that, it would still be a long time before we could get to the point of building commercial fusion power plants. Beyond the technical questions, it's an issue of how much we spend.” He directed his attention to the students. “That brings me to a last question: how much do we spend in the US per year on fusion energy research?”

A number of students shouted out amounts ranging from one billion dollars to fifty billion dollars.

“Not even close. How about two hundred million dollars? In a country that has been energy-dependent, we spend less on this than on studying the mating habits of various animals, less than on bridges that go nowhere, and a fraction of what the President of the United States spent on his campaign.”

“Isn't that because people aren't sure it can ever work?” one student asked.

“Personally, I think it is more about energy politics than anything else. After all, look at the tens of billions of dollars the government spends every year on ideas that can't possibly provide the amount of energy we need.”

One student asked, “Is there anything we can do about this?”

Viktor answered, “It would help to have an informed and involved electorate.” In truth, he thought the odds against that were very high. Just look at how little effort people put into understanding financial markets, government and trade deficits, and the state of education. After all, writing something witty on Facebook or Twitter already took up a lot of their time. In this willfully knowledge-limited world,
emotional self-certainty was more than enough to fuel support for candidates.