Tammy Ma was about to board a plane at the San Francisco International Airport when she got the call of a lifetime. She’s a plasma physicist at the National Ignition Facility (NIF), the world’s largest and most energetic laser. An experiment at the facility had just accomplished a breakthrough in nuclear fusion that scientists have been trying to achieve for decades. 

“I burst into tears, and I was jumping up and down in the waiting area,” Ma told reporters at a technical briefing on the achievement in Washington, DC, this week.

Very early that morning — 1:03AM on December 5th — NIF shot 192 laser beams at a tiny target filled with fuel and achieved “fusion ignition” in a controlled setting for the first time on Earth. That means that they’d been able to generate more energy through nuclear fusion than the laser energy used to kick off the reaction. By producing fusion reactions in the lab, Ma and her colleagues essentially recreate the way stars generate energy. And one day — albeit likely decades from now — that process could power our world with clean, theoretically limitless energy. 

The Verge has an explainer on nuclear fusion and the breakthrough with ignition that took place this week. We also interviewed Ma, who leads the Inertial Fusion Energy Institutional Initiative at the Lawrence Livermore National Laboratory. Check out our conversation to learn more about her work and what breakthroughs come next after ignition.

This interview has been edited for length and clarity.

How would you describe your day job at Lawrence Livermore National Laboratory?

Let’s be honest. We’ve got this ensemble of data now from the past decade that we’re building off, so it’s not like we’re pulling new ideas out of the air. But you know, how do we improve on the last set of experiments? What design changes do we want to do?

We work with the laser scientists to try to define the best laser pulse that we can use. We have to work with material scientists to develop the materials for the targets that we need. We work with experimentalists that have to set all our diagnostic instruments to exactly capture the burst of neutrons when it comes out. We have some of the fastest X-ray cameras in the world, so we can actually record what’s going on in real time. So in total, it’s a huge team that brings all this together.

My particular role right now, though, is actually trying to move toward the next step of fusion energy. We’ve been trying to prepare, you know, after we get ignition, how can we capitalize on this great discovery? And now we’re here.

What was it like getting the news that your lab had achieved ignition?

It was amazing because the NIF runs 24/7 — we are doing experiments every single day. And it’s just built on decades of work, right? And I’m very lucky to be here at this time. But there’s been giants that came before us. And I’m still not sure it’s fully sunk in yet that we’ve achieved this. So it’s exciting.

And when will you try to achieve this again?

We’re going to continuously not only try to repeat the shot but to also implement improvements in the future. We are continuously trying to improve the quality of the targets — that makes a huge difference. We have plans to continue turning up the laser energy in the future. Every couple of weeks, we are doing new experiments.

What challenges need to be overcome next?

We also have to build up many of the underlying technologies that will support a fusion power plant in the future. But that means cheaper targets that we generate at high volume and that are very robust and good quality. Bringing in lasers that can run at a high repetition rate. The NIF only shoots once every four to eight hours or so. But it’s envisioned that a fusion power plant would have to shoot 10 times a second or more. So, you can imagine, we have to figure out a way to speed everything up. It’s a big challenge. And so we do have to work not just with a huge team at the lab, but we work with universities and academia. The private sector is getting interested now, too. And so we need all of that expertise to come together and make it happen.