SSGF Alumna on Historic NIF Team

Ames, Iowa
Thursday, February 13, 2014

A team of researchers that triggered landmark fusion reactions includes an alumna of the Department of Energy National Nuclear Security Administration Stewardship Science Graduate Fellowship (DOE NNSA SSGF).

Laura F. Berzak Hopkins, a fellow from 2006 to 2010, is one of 22 authors on the history-making paper published in the Feb. 13 issue of Nature. The team reports on inertial confinement fusion (ICF) tests that produced more energy than the fuel put into the reactions.

The experiments at Lawrence Livermore National Laboratory’s National Ignition Facility (NIF) focus powerful lasers on the interior of a gold cylinder about the size of a pencil eraser that contains a pinhead-sized plastic pellet lined with frozen hydrogen isotopes.

The lasers heat the gold, creating a plasma and generating powerful X-rays that rapidly burn off the capsule’s plastic covering, imploding the pellet with such force and speed that the isotopes fuse, releasing energy.

The Nature paper reports that for the first time these ICF experiments produced more energy output than the fuel put into the experiment. Ultimately, the goal is to produce more energy than the lasers put into the reaction, creating a source of clean, abundant power.

Under the DOE NNSA SSGF, Berzak Hopkins received a doctorate in plasma physics from Princeton University in 2010 and completed a practicum at Sandia National Laboratories. Now a Livermore Lab physicist, she participates in ICF research that has taken the field a major step forward.

Berzak Hopkins has worked closely with physicist Sebastian Le Pape leading up to the experiments published in the Nature paper. “My role is to take the as-shot laser pulse, study the shock structure it delivers to the capsule and tune the shocks,” she says. “We want them to merge at very specific points within the capsule” – the 2-millimeter-diameter plastic sphere containing a mixture of deuterium and tritium, the hydrogen isotopes used as nuclear fusion fuel.

She also is part of the larger team that determines how to adjust the frequency of the laser beam bundles so energy is redistributed between beams, improving implosion symmetry.

The Krell Institute of Ames, Iowa, administers the Stewardship Science Graduate Fellowship for the Department of Energy National Nuclear Security Administration. The fellowship provides excellent financial benefits and professional development opportunities to students pursuing a Ph.D. in fields of study that solve complex science and engineering problems critical to stewardship science.