Laura Berzak Hopkins launched her career in fusion energy research as an experimentalist at the Princeton Plasma Physics Laboratory (PPPL) in her home state of New Jersey, working on magnetic confinement fusion.
She designed, built, and installed diagnostics on PPPL’s Lithium Tokamak Experiment (LTX), a medium-scale spherical tokamak (a device that uses a magnetic field to confine superheated plasma, in contrast to the inertial confinement fusion (ICF) technique used at NIF).
The LTX was built with a secondary interior metal shell to serve as a lithium-coated boundary for the magnetically confined plasma. Laura’s dissertation work was to design and demonstrate the sequence of magnetic fields necessary to start up and sustain a fusion plasma in LTX, which she completed with the aid of novel magnetic-field modeling techniques.
Before starting work at LLNL in 2012, Laura closely followed the research and achievements of the NIF Team, always thinking of NIF as an exciting and unique facility. Moreover, the people she met and interacted with at LLNL and at NIF were passionate about their work, and were both welcoming and willing to share their experiences.
Laura is now a member of the ICF team at NIF. She works on target and laser design for a variety of NIF experiments, and she focuses on exploring the use of near-vacuum hohlraums to increase the efficiency of the energy transmitted from the hohlraum to the target capsule. She says her work centers predominantly on high-density carbon (diamond) capsules in near-vacuum and low-gas-filled hohlraums. “This is exciting work that is geared toward understanding fundamental physics,” she explains, “as well as making progress toward higher-yield targets. It is exciting to be thinking about both priorities.”
She also spends time shock-timing pulses using “keyhole” targets, which involves fine-tuning the relative timing at which different shocks generated by the laser drive interact with and implode the capsule. In addition, she leads a Laboratory Directed Research and Development (LDRD) program which involves adding a xenon dopant to the capsule gas-fill to study xenon isotopic activation.
Asked how her love for science began, she explains that her grandfather, a chemist, might have kindled her interest by demonstrating small experiments for her and her brother. She recalls one experiment in particular in which he made ink in the kitchen sink—it left a mess, and left his grandchildren wanting to learn more.
Though she double-majored in chemistry and physics as an undergraduate at Dartmouth, Laura says it was physics that proved to be her passion. She secured a student internship at PPPL in the fall of 2002, which she described as “an eye-opening opportunity.” PPPL researchers were excited to share their experiences with her as an intern, and her experience there solidified her journey and career path towards plasma physics and fusion science.
After receiving her Ph.D. from Princeton University in 2010 for her work with LTX, Laura took a couple of years to focus on science and research policy in Washington, D.C., which she describes as an “unparalleled opportunity to learn about the political aspects of science policy.” As the 2010-2011 American Physical Society Congressional Fellow, she was able to work on drafting science-based legislation as a legislative assistant in the office of Senator Kent Conrad of North Dakota, who led the Senate Budget Committee, and as a scientific advisor for the House of Representatives Foreign Affairs Committee’s Subcommittee on Terrorism and Nonproliferation.
She found it both necessary and fascinating to apply her scientific background to non-research science problems in order to provide data-driven answers to difficult technical questions. However, she says, “I missed or felt removed from the quantitative challenge of doing research,” since her legislative work “was more qualitative, but a great learning experience.”
Looking back on her scientific career path to date, she observes, “There are not a lot of women in science, but in the ICF program here at Livermore, there are fantastic role models.” She never felt particularly deterred by the scarcity of women, but rather has taken it as a challenge to help young women of all ages pursue careers in science, particularly in plasma physics.
To this end, Laura is regularly involved with youth events, such as LLNL’s “Fun with Science” program. She enjoys seeing the positive energy of middle school students in response to table-top demonstrations. She believes that much can be gained by spurring the curiosity of these students through basic experiments, like putting a balloon or glove in liquid nitrogen, imploding a marshmallow man in a vacuum chamber, or using a Tesla coil to “shock” her husband (a theoretical physicist who sometimes serves as her assistant).
She also participates in Expand Your Horizons, a program that introduces middle-school girls to science and technology, and she finds time to manage a small program she started in 2013 called “Why-Sci”, a Web-based platform that enables non-scientists to learn about ongoing research through brief articles written by the researchers.
Currently, she is gearing up for an important NIF experiment this month, a diamond-capsule cryogenic layered deuterium-tritium (DT) experiment which she hopes will grow our understanding of materials physics in near-vacuum hohlraums. “There is a lot going on, and it is exciting, but also nerve-wracking,” she admits. “Research science has question marks, and with research questions, you don’t know the answer before you begin.
“At NIF—from laser engineering, to target engineering, to the actual firing of targets—each shot is not only its own research project or experiment, but NIF as a whole is a research project in its own right. The longer I work on NIF, the more amazed I am at how many challenges have had to be overcome, and the incredible scientific and technical feat of the facility…so many variables are being brought together. It’s very exciting to be working here.”
When she’s not doing physics, Laura enjoys playing the violin and piano. She also points out that her and her husband’s physics backgrounds come in handy with restoration projects around the house—although she admits that “theorists and experimentalists don’t always see eye-to-eye when it comes to cutting tile.”