Danny Cai


Mechanical engineer

“Fusion energy is going to be another revolution for humankind. I think most of us engineers here are excited and want to contribute to that goal.”

I am the Lab: Danny Cai

PPPL’s approximately 600 employees support the Princeton Plasma Physics Laboratory’s primary scientific mission to develop the scientific understanding of plasmas and to develop the knowledge and engineering to enable fusion energy to power the U.S. and the world. Each month we profile one of our employees at our national laboratory who exemplifies the wide variety of backgrounds, talents, and interests of our staff.

I am the Lab: Danny Cai’s lifelong interest in energy led him to his work as a mechanical engineer on PPPL’s fusion experiment

“Fusion energy is going to be another revolution for humankind. I think most of us engineers here are excited and want to contribute to that goal.”

Name: Danny Cai:

How long at PPPL: Since 2014 

Position: Mechanical engineer

Deng (Danny) Cai grew up in the city of Wuxi, China. When he came to the U.S. for graduate school in 2001, he had two suitcases and a few thousand dollars. He stayed to become a U.S. citizen, got married, and started a family. He is an engineer on PPPL’s fusion experiment, the National Spherical Torus Experiment-Upgrade, and volunteers as a tour guide.

Cai has always been interested in energy. When he was young, he saw a movie with a nuclear fusion reactor and never dreamed he would actually get to work on one. Cai’s family in China lived near an electrical plant, and he at first thought he would study engineering and get a job at the plant, which was two miles away. He did an internship at the plant but then became interested in solar energy. He obtained his bachelor’s and master’s degrees in mechanical engineering at Xi’an Jiao Tong University in China before coming to Stony Brook University in New York to earn his Ph.D. in engineering where he focused on applications of silicon to the solar industry.

After graduating in 2007, Cai worked at CVD Equipment Corp. on Long Island, where he and other engineers developed silicon for industrial applications. He applied for an engineering position at PPPL and joined the staff in 2014. “I was really excited because the position fits me very well,” he recalled. “My knowledge is useful here.”

Cai said he is especially excited to be able to contribute to PPPL’s primary mission of developing fusion energy as a sustainable, abundant and affordable source of electricity. “I never thought I could work in this area before,” he said. “It’s really something that humankind can benefit from, and I believe if fusion energy is successful it’s going to be another revolution for humankind. I think most engineers here are excited and want to contribute to that goal.”

Cai met his wife, Vicky, a process engineer, in graduate school, and the two married in 2009. They live in West Windsor, New Jersey, with their children, Elizabeth, 9, and Angela, 2.

Please describe your job:

“I’m the responsible engineer for vacuum fueling systems for the National Spherical Torus Experiment-Upgrade and I’m also the cognizant engineer for the center stack casing and the cooling system design and for the NSTX-U coil bus design in the test cell.“

Three things about yourself:

“I like soccer. I’ve been a big soccer fan since I was a teenager. I enjoy watching the U.S. women’s team because they’re very good, and the World Cup. The World Cup is like a big festival for me.”

“I like the national parks. They are really fantastic and beautiful. I have visited lots of national parks in the U.S. already and some of them multiple times.”

“I like to cook. In my spare time, I try lots of Asian food, like Chinese food, Japanese food, and also Korean food, sometimes Thai food. I research the recipe and just see if I can repeat and improve.”

What does working at PPPL mean to you?

“As an engineer I consider myself very lucky to have this kind of job. We are considering the next generation fusion machine here and you can see the really challenging part is engineering. We’re pushing to the limit of our current knowledge. A lot of it is a challenge and there are always new things to learn. You never get bored.”