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“Stellar” progress on NSTX-U highlights strong year for PPPL, Lab Director Stewart Prager says

The U.S. Department of Energy’s Princeton Plasma Physics Laboratory (PPPL) is looking forward to reopening the National Spherical Torus Experiment (NSTX-U) after “stellar” progress in the $94 million upgrade of the facility that should allow it to be completed by December of this year, Lab Director Stewart Prager told PPPL staff during his annual State of the Laboratory speech on April 29.

NSTX-U is the experiment at the heart of PPPL’s research activities and will make the facility the most powerful tokamak of its type in the world. The two main components of the upgrade, Prager said, are the center magnet or center stack, and a second neutral beam that injects neutral atoms into the ionized gas, or plasma, to heat the plasma to temperatures of about 100 million degrees Centigrade. Those components will double the current, double the heat and quintuple the duration of the plasma.

Great progress over the last year

“We’re building a scientific tool for the country and the Laboratory and there’s been great progress over the last year,” Prager said. “To date, every technical challenge has been met and there have been many of them.”

The second neutral beam is already in place in the NSTX and the center stack magnet is being constructed, Prager said. The center stack magnet is really two magnets in one: copper bars that go straight up and down create one magnetic field and a coil around the center stack is a second magnet that drives a current through the plasma. It was constructed in four quadrants, which were then assembled and insulated.

“This requires incredible engineering and craftsmanship and it’s gone extremely successfully,” Prager said. “We’re 85 percent in completion of the upgrade.”

Prager noted that the U.S. Department of Energy has strongly supported the NSTX-U project despite the ups and downs of federal funding. “This is a fantastic result for this year and I hope next year we’ll be talking about the initial experiments on the NSTX-U,” Prager said.

The NSTX-U will allow researchers to produce “a sustained high pressure plasma” over the next decade, Prager said. Researchers also hope to discover “novel solutions” for the plasma material interface, the contact between the plasma and the plasma-facing components. That will be an essential task not only for PPPL but also for developing magnetic fusion in general, Prager said.

A smaller device, PPPL’s Lithium Tokamak Experiment, has been operating with a liquid lithium surface and has had “very favorable results,” Prager said. One long-term goal is “to have LTX become more integrated into the NSTX-U program,” he said.

Role in ITER

The next step in developing magnetic fusion as a clean, abundant and safe energy source is the international fusion experiment ITER in Cadarache, France. PPPL is strongly contributing to ITER, Prager said. For example, PPPL is designing and engineering diagnostic port plugs and is responsible for delivering the facility’s steady-state electric power network, Prager said.

Prager noted that Richard Hawryluk returned to PPPL after working on ITER for two years as Deputy Director General for the Administration Department. Hawryluk received a certificate of appreciation from U.S. Secretary of Energy Ernest Moniz.

Despite some press reports of management challenges at the international facility, Prager said, “ITER is actually being constructed. And when ITER is constructed, it will be a landmark scientific experiment for the 21st century, so we shouldn’t lose sight of that.”

But ITER won’t solve all the problems of nuclear fusion, Prager said, and researchers are looking ahead to a fusion nuclear science facility (FNSF) that could eventually lead to a demonstration plant. PPPL’ers are involved in preliminary research for an FNSF, Prager said.

PPPL’s theory and computation research is also essential to the Laboratory, Prager said. PPPL researchers last year were awarded more than 275 million core hours on supercomputers to study the plasma edge and plasma confinement, the equivalent of some 20,000 years of computer time, Prager said.

Budget ups and downs

The national budget for fusion energy research has been a “roller coaster ride for the research program,” Prager said. After dipping from 2012 to 2013 it was back up to $306 million for research and $200 million for ITER in fiscal year 2014. The 2015 budget is not known but the Obama Administration has proposed a $266 million budget for research with $150 million for ITER.

PPPL’s funding from Fusion Energy Science also dipped from 2012 to 2013. The FY 2014 estimated budget for PPPL totals $96 million, including $80 million from FES. However, the Administration’s request for PPPL in 2015 is $75.5 million, for a total PPPL budget of $92 million.

The good news is that the 2015 budget could include an additional $25 million for infrastructure improvements, as part of an overall campus plan. “This is fantastic,” Prager said. The plan would look at updating PPPL’s laboratories, particularly for smaller experiments; modernizing office spaces, particularly in the Theory Department and the Environment, Safety, Health & Security Department; and upgrading electrical and mechanical infrastructure.

Other new experiments & collaborations

In addition to PPPL’s main experiment, the Laboratory has also moved ahead with several new experiments and collaborations, Prager said. One such facility is a new version of the Magnetic Reconnection Experiment called FLARE to study magnetic disturbances that cause northern lights solar flares, geomagnetic disturbances, and numerous astronomical phenomena. FLARE will be three times bigger and much powerful than the current device. It will be constructed over three years and will be funded through $3 million from the National Science Foundation and $1.2 million from Princeton University, Prager said.

PPPL also began the Center for Heliospheric Physics, a joint project with the University’s Department of Astrophysical Sciences, that will study the space surrounding the sun where violent space weather can interrupt cell phone service, damage satellites and knock out power grids.

Researchers at the Laboratory have also pursued numerous collaborations nationally and internationally, including the Max-Planck/Princeton Center for Plasma Physics, a collaboration between Princeton University and the Max Planck Society of Germany.

PPPL researchers are also working on “fledgling” studies of plasma-based nanotechnology and are resubmitting a proposal to the DOE for research into this field, Prager said.

Other technologies being investigated at PPPL include a plasma mass filter that could potentially be used to clean up large amounts of radioactive waste. Researchers are also working on X-ray imaging techniques that could have “enormous impact in a huge array of applications,” Prager said.

PPPL and U.S. Department of Agriculture researchers are developing a technique that uses radio frequency waves to pasteurize eggs. Princeton University and PPPL researchers are also working on a method to verify whether presumed nuclear warheads being decommissioned actually are nuclear warheads.

“All of this diversity of activities does not add up to a huge pile of money,” Prager said. “However, it leads to huge scientific creative activity at the Laboratory, so in that way it's incredible.”

Collaborations around the world

Prager said that while NSTX-U has been under construction for the past three years, PPPL researchers have been busy analyzing previous data from the experiment and collaborating with laboratories around the world. Researchers at PPPL published 60 articles in journals over the past year, including four in the prestigious Physical Review letters.

He noted that three Office of Communications staff members: Science Writer John Greenwald, Photographer Elle Starkman, and Webmaster Chris Cane, received awards from the Council for the Advancement and Support of Education District II last year.

Prager recognized physicists David Gates and Charles Skinner, who received the prestigious honor of being named APS fellows last year.  He also cited Robert Cutler, a technician at PPPL for the past 34 years, who recently received Princeton University’s Presidential Achievement Award for his work at the Laboratory.

RGDX and outreach

Some of PPPL’s research is geared toward educating and informing students and the general public, Prager said. One example is the Remote Glow Discharge Experiment (RGDX) devised by Science Education Postdoctoral Fellow Arturo Dominguez. The RGDX allows users from anywhere in the world to log on to a program where they can create and manipulate a glowing plasma in a device in a PPPL laboratory, and watch their results in a video stream.

PPPL had a hugely successful outreach event in June of 2013 when the Laboratory opened its doors to the public and some 3,000 people visited the Laboratory, Prager said. 

Safety continues to be a big priority for the Laboratory, Prager said. He urged staff to continue taking part in a quarterly survey so that PPPL can continue to improve. The Safety Champions Committee is also coming up with a list of recommendations to address some of the concerns raised in the survey.

Praise for hard work of Facilities crews

Prager showed photos of the Lab during one of the numerous winter snowstorms this year and joked that “it was a beautiful winter for cross-country skiing and enjoying the cold.” The audience applauded when Prager remarked that everyone should appreciate the hard work of the Facilities group. They “worked through the night to ensure that the Lab could open safely and people could come to work in the morning,” he said.

Prager told PPPL’ers that the past year “was a good year for the fusion program and a great year for us.” He added that PPPL has “planted the seeds for an even greater harvest next year.”

U.S. Department of Energy
Princeton Plasma Physics Laboratory is a U.S. Department of Energy national laboratory managed by Princeton University.

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