High-energy-density physicist Danae Polsin ’13 and professor of physics Stephen Padalino explain experiments that recently harnessed the same energy produced by the sun and stars — and what it may mean for the future of energy.

By Robyn Rime

Among physicists, there is an old joke that fusion is 50 years away — and always will be. 

That timeline may have shortened, though, thanks to a recent experiment at Lawrence Livermore National Laboratory in California, where scientists for the first time ignited a nuclear fusion reaction that produced more energy than went into it. 

That breakthrough event ignited excitement in the world’s scientists as well. If humans can harness that power — the same power behind a universe of shining stars — then they may hold the key to clean, nearly limitless energy and arresting global climate change. 

“This is the first time this has been done in a laboratory setting anywhere in the world,” says Danae Polsin ’13, PhD. “It’s important because it shows that it can be done.”

Polsin, who is not directly involved with the Livermore experiment, earned her bachelor’s degree in physics at Geneseo with Distinguished Teaching Professor Stephen Padalino and is now an experimental scientist in the University of Rochester’s Laboratory for Laser Energetics (LLE), and assistant professor of mechanical engineering at the U of R. Her doctoral work included research conducted at LLE and Livermore’s National Ignition Facility (NIF), a longtime collaborator with LLE. 

“This will go down in science and history as a phenomenal discovery,” says Padalino. “Scientists don’t tend to jump up and down a lot and yell and scream. But you know, for this they actually did.”

Here Polsin and Padalino break down the recent experiment and its long-term implications.

Scientists have been working toward this for decades—why was it so difficult?

  1. It’s difficult to maintain the conditions necessary for fusion to occur, says Polsin. To get light atoms to stick together — to fuse — and then release the energy stored in their mass, NIF used 192 lasers, combined into the most powerful laser in the world, to heat and compress a fuel pellet the size of a peppercorn to a temperature hotter than the sun’s core. And NIF tried hundreds of times before they succeeded. 
  2. The reaction is tremendously difficult to measure. How do you know if the experiment succeeded when it lasts less than a billionth of a second? “Many of the diagnostics had to be invented for these experiments,” says Padalino. “For example, where do you get a camera that can take 16 pictures in less than a nanosecond or a thermometer that can measure 20 million degrees? You don’t find those at Wal-Mart or Amazon. You’ve got to build all those things.” 
  3.  NIF didn’t succeed alone. Thousands of people in the US and worldwide collaborated on this five-decade long effort. “It’s like a moonshot program,” says Padalino.

Why should the average person care about the results?

  1. Commercial fusion energy could impact climate change. Fusion is both clean (it doesn’t emit carbon) and the fuel is nearly limitless (it can be produced from seawater), and it could vastly reduce our dependence on fossil fuels. 
  2. The US could better maintain and improve its nuclear arsenal. Fusion experiments like these are used to test computer-aided designs for nuclear weapons, and better testing would mean stronger national security. “For example, the last nuclear test we did was around 1991,” says Padalino. “The absence of testing is like parking your fire truck for 30 years and hoping that it works when you need it — never a good idea for national defense. These experiments also telegraph to our adversaries that we have a viable and effective nuclear deterrent.”
  3. The new science generated from this work is extraordinary. “This gives us the opportunity to do discovery science on a scale that’s never been done before. We can now investigate temperatures and pressures not found anywhere in our solar system,” says Padalino. “Modern civilization is founded on the discoveries of the past five decades. Future societies will be based on the discoveries of today, like this one.” 

What’s preventing us from moving forward now? 

The technological, scientific, economic, and design obstacles are considerable, says Polsin. Can NIF repeat their results? Can they scale it up, make it cost effective and, importantly, more efficient? True, NIF used two units of laser energy to produce three units of fusion energy—but that counted as a net positive only because NIF’s equation didn’t include the 300 units needed to power the lasers in the first place. 

If there are so many hurdles, why is everyone so excited?

“This breakthrough is giving us the confidence to move forward and ask what we can do to make the timeline shorter,” says Polsin. “That’s what makes this research fun—it was a super difficult problem to achieve, it takes a huge team, and we’re all just excited to be a part of it. In my opinion, I have the best job in the world.”

 

BONUS INFO: Want to learn more? Distinguished Teaching Professor Stephen Padalino says this “60 Minutes” segment illustrates the reaction well and discusses the complexities for the future.