Measuring Plasma Temperature During NIF Shots

Nick Parrilla first became fired up about NIF after hearing LLNL physicist Thomas Dittrich speak to his high school physics class. Naturally, he’s thrilled to be working this summer as a NIF & Photon Science summer scholar.

"I remember hearing the talk, hearing about all the great research that goes on here," said Parrilla, 21. "It’s what made me want to major in physics in the first place."

Parrilla will return to Case Western Reserve University in Cleveland, Ohio, in September to start his senior year following his second stint as a summer scholar.

NIF physicist Joe Ralph put him in charge of a project to employ x-ray diagnostics to measure the temperatures of plasma that is being pushed just outside the hohlraum’s laser entrance holes during NIF shots (see "How NIF Targets Work").

Parrilla is using diagnostic tools and filters that NIF scientists built a couple of years ago, but have not had time to use, Ralph said.

"This is the first time they’ve been analyzed like this," he said. "So, having him as a summer student is just great."

And with the previous summer’s experience under his belt, "he’s hit the ground running right away," Ralph said. "He is driven. He puts a lot of work in, he’s highly motivated, he catches on very quickly. He has his own ideas. And he’s always pushing me to look at newer things or extend what we can see."

Parrilla first heard about the Laboratory in 2014 when Dittrich, of the Design Physics Division, visited his class at St. Edward High School in Lakewood, Ohio, to talk about NIF and inertial confinement fusion research. Dittrich graduated from the suburban Cleveland school in 1966.

First Choice

After entering college, Parrilla thought again about LLNL when he started looking for potential internships. "This was the first place I applied to," he said. "I thought it was a natural progression."

He contacted Dittrich to learn more and was selected for Lab internship in 2017.

"Nick is a very hard worker," Dittrich said. "I have spent considerable time with him and have seen him grow professionally to be a significant contributor to his project. Nick is also very focused on his goal of attaining a PhD in physics and perhaps working at a national lab such as LLNL."

Dittrich said his experience with Parrilla shows the impact Lab scientists and their work can have on students.

Reaching out to students "at the high school level is extremely important," he said. "Students at that age are starting to make career decisions and are very interested in what is out there."

Once he started at NIF, Parrilla’s biggest challenge was learning about everything involved in the project.

"I read a lot of papers, read a lot of text books, went to a lot of meetings," he said. "The most difficult part was something that I came across last summer, just being overwhelmed by how much there is going on in one of these experiments. There are acronyms for everything. So, learning how everything’s set up and works is definitely the first hurdle."

Last summer, Ralph "really guided me and gave me a lot of information when I needed it," Parrilla said. "This summer, I’m allowed to experience just being an independent researcher, asking questions about what’s going on and looking into it myself and not having any required direction I need to go in or anything I’m told to do."

He’s learned a lot from both experiences.

"I definitely needed the help last summer," he said. "And this summer, I think I’m really maturing as a researcher by getting to lead this project."

Ralph hopes Parrilla’s work will eventually help NIF recover more plasma temperature data from inside the hohlraum as well.

"I’ve talked about how we can apply some of the same principles to other diagnostics," Ralph said. "The methods are similar to extract the information, but it would be more relevant to the temperature inside. So, we’re hoping to get that down the road."

And five years down the road, Parrilla hopes he’s back at NIF.

I’d love to work here, although I might still be in graduate school," he said. "If not, I would love to be involved in fusion research somewhere."