VOL. 7, NO. 3 • SUMMER 2003

New Stellarator Project Underway

An Interview with Hutch Neilson 

On April 1, the National Compact Stellarator Experiment (NCSX) was officially granted Project status by the U.S. Department of Energy. A successful Conceptual Design Review, which focused on physics, was held in May, 

2002. A Preliminary Design Review, which will examine engineering design, as well as cost and schedule issues, is 

scheduled for this October. Contracts have been awarded for the fabrication of prototype components to begin in 

January. The new machine will be built at PPPL's C-Site, with first plasma scheduled for June of 2007. Recently, 

Hotline staff interviewed NCSX Project Head Hutch Neilson to learn about this exciting new venture. 

Hutch Neilson

How did you first become interested in stellarators? 

I became interested in stellarators in the early 1980’s when 

I was at Oak Ridge National Laboratory (ORNL). We built 

a stellarator called the Advanced Toroidal Facility (ATF). 

I was responsible for preparing the ancillary systems, the 

power supplies, diagnostics, plasma heating systems, and 

so on, and pulling everything together to achieve the first 

plasma milestone. 

What interested me about stellarator physics was the threedimensional structure of the magnetic field and the plasma 

shape. The cross-sectional shape of a 3-D plasma depends 

on where the torus is sliced, while the cross-sectional shape 

of a tokamak, a 2-D torus, is always the same. Consequently, 

stellarator physicists have three degrees of freedom to tailor 

the plasma shape for good performance. There are only two 

degrees of freedom in a tokamak.

I had worked on tokamak magnetic diagnostic data analysis. 

I became fascinated with the idea that stellarator coils could 

generate a spiraling magnetic field without the plasma current needed in a tokamak. I began trying to understand high 

pressure stellarator equilibria and how to infer their properties from magnetic data. It was a much more difficult task 

than I expected, and I didn’t get very far. Today there is a 

national team, led by some of our best researchers, working 

on the 3-D magnetic data analysis problem. So I don’t feel 

so bad about my lack of progress working on it part-time 

back in the 1980’s.

Can you reflect on how it feels to return to a concept on 

which PPPL was founded?

Continued on page 2
PPPL NEWS • Summer 2003 Page 2

 The PPPL NEWS is issued by the Princeton Plasma Physics Laboratory, a research facility supported by the United 

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should be directed to: Information Services, Princeton Plasma Physics Laboratory, P.O. Box 451, Princeton, NJ 08543; 

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PPPL NEWS

Information Services Head: Anthony R. DeMeo

Editor/Writer: Patti Wieser

Photographer: Elle Starkman

Layout and Graphics: Gregory J. Czechowicz 

 and Patti Wieser

Continued from page 1

Stellarator

Continued on page 3

 

Lyman Spitzer believed that we would make a lot of progress 

in plasma physics and performance with tokamaks, but that 

the stellarator would make the better reactor because it is 

more straightforward to make it run steady-state. I think it 

is fitting that the Laboratory, after making historic advances 

with tokamaks, has turned to the task of expanding our understanding of toroidal configurations to find the best solution for magnetic fusion reactors. For instance, just as we 

are using the National Spherical Torus Experiment (NSTX) 

to push into new physics regimes, we will use NCSX to 

understand how to use 3-D fields and plasma shaping to 

optimize performance. We are encouraging and supporting 

other institutions that are tackling different aspects of this 

difficult challenge. It is a challenge that is worthy of PPPL’s 

talents. This is what attracted me to join the Laboratory staff 

in the mid-1990’s. But more importantly, I believe Professor Spitzer would approve and be proud of us for taking on 

these important problems.

What are the advantages of a stellarator compared to other 

magnetic confinement configurations?

The basic conditions for good magnetic confinement are a 

toroidal geometry and a magnetic field that twists around 

helically on magnetic surfaces. A stellarator can create 

those conditions with coils alone. It doesn’t require a 

plasma current. That means it is easy to make a stellarator 

steady-state. Also, stellarator plasmas typically don’t disrupt. These advantages result from the three-dimensional 

nature of the stellarator. Its coils and vacuum vessel have 

more complex shapes than those of tokamaks and this carries a cost. However, it also carries enormous opportunity 

for improved performance. As I noted earlier, a stellarator 

gives designers three degrees of freedom to tailor the plasma 

shape for good performance. We now have good enough 

physics models and computer power to do this, and this is 

how modern stellarators, such as NCSX, are designed. With 

these experiments, we can test physics solutions that will 

lead to practical reactors. We can study 3-D physics effects 

that are important for all magnetic configurations, but should 

be much easier to see in a configuration that is itself 3-D. 

A goal of our research is to quantify both the benefits and 

the costs, giving the designers the information they need to 

optimize future devices.

Where are the major existing stellarators located? 

Japan and Germany both have long histories of stellarator 

research and are the leaders in the field. Japan has a TFTRscale superconducting stellarator, the Large Helical Device 

(LHD). The Germans are building a large superconducting 

stellarator, the Wendelstein 7-X, the next step in their stellarator line. This follows the recent closure of their W7-AS 

stellarator experiment in Garching after a successful run of 

almost 15 years. The W7-X is being built in Greifswald in 

the former East Germany. Spain, Australia, and the United 

States also have operating stellarators. Our new stellarators, 

the NCSX here and the Quasi Poloidal Stellarator (QPS) 

to be built at the Oak Ridge National Laboratory (ORNL), 

will not be among the world’s largest, but they will develop 

physics ideas that will lead to more compact stellarator power 

plant designs. The U.S. compact stellarator designs have 

much lower aspect ratios than previous stellarators. They 

are closer to tokamaks in that respect. Moreover, they have 

strong physics ties to tokamaks, so they can take advantage 

of, and build on, all the progress we have made with tokamaks — nothing is thrown away.

How did the idea of a compact stellarator evolve? Will 

NCSX be the first compact stellarator in the world?

The seminal ideas originated with theorists, many of them at 

PPPL, who in the early 1980’s explained how the confinement properties of a stellarator depended on the details of the 
Page 3 PPPL NEWS • Summer 2003

magnetic-field structure. By incorporating that understanding 

into computer codes, we have been able to design stellarator 

configurations to meet physics specifications. Those designs 

can then be built and tested to validate the physics models. 

The W7-AS and the University of Wisconsin’s Helically 

Symmetric Experiment (HSX) are the first examples of this 

new approach. It is a dramatic departure from the cut-andtry approach to experiment design that we used to take. It 

came about because both our physics understanding and our 

design capabilities matured to the point where we can target 

the characteristics we want in our designs. That allows us to 

design better experiments that are more precisely targeted 

to the questions we want answered, to take larger steps, and 

consequently to make faster progress.

The compact stellarator strategy actually combines several 

ideas. One is magnetic quasi-symmetry, which means that 

even though the plasma shape is three-dimensional, the 

magnetic field has a symmetry direction, just as a tokamak 

or a spherical torus does. HSX is now testing this idea on a 

small scale, and it is working very well. As a quasi-axisymmetric stellarator, the NCSX has a strong physics overlap 

with the tokamak. In fact, a charged particle following a 

magnetic field line around in NCSX would think it was in 

a tokamak. That is, the charged-particle orbit confinement 

is the same as in a tokamak, so we believe that some of 

the tokamak’s good performance features will carry over 

to NCSX. Unlike previous stellarator designs, the NCSX 

is optimized to be both quasi-axisymmetric and stable at 

finite pressure in a compact configuration. The result is a 

passively stable configuration that relies on the shape of 

the coils rather than active feedback and current drive to 

maintain a high-performance stable plasma. A fusion power 

reactor based on this approach would have power densities as 

high as a tokamak, but would operate with a higher overall 

efficiency, because it would not need to recycle any power 

to drive current and plasma rotation. It would have more 

complex coil geometries than a tokamak, but would be a 

simpler and more reliable system overall.

The QPS experiment proposed by ORNL is a smaller, higherrisk experiment designed to push stellarators to aspect ratios 

less than 3.0. Auburn University is building a small stellarator, the Compact Toroidal Hybrid (CTH), to explore plasma 

physics issues in support of NCSX. As you can see, NCSX 

is not an isolated experiment but part of a national program 

that includes theory and multiple experiments to develop 

the knowledge base needed to assess the attractiveness of 

the compact stellarator concept and decide on a major next 

step by 2011 or 2012.

What was the genesis of the National Compact Stellarator 

Experiment?

In 1996-1997, several working groups were formed at PPPL 

to come up with new initiatives for the Laboratory. There was 

one on stellarators looking at quasi-axisymmetric configurations. At the same time, other groups around the country, 

including the ORNL stellarator group, were also interested 

in modern optimized stellarators. A national program planning committee drafted a blueprint for a national stellarator 

proof-of-principle program, with NCSX as its central element, to develop the compact stellarator. In 1998 PPPL and 

ORNL formed a partnership to propose and carry out the 

NCSX project by pooling our talents in stellarator physics 

and engineering. A national advisory committee was formed 

about the same time and has guided the project ever since. 

The project has been debated in many forums and passed 

several major peer reviews, including a physics validation 

review in 2001 and a conceptual design review in 2002. 

The fabrication project was approved by DOE last fall and 

officially started on April 1.

What is the overall timeframe for the design, construction, 

and operation of NCSX?

This year we are continuing with the design and are starting R&D to determine exactly how the modular coils and 

vacuum vessel, the most challenging components, will be 

manufactured. We recently placed contracts with industry to 

develop the manufacturing processes and build prototypes for 

the winding forms and the vacuum vessel. We are developing 

the coil winding methods here at PPPL, and are planning to 

wind the NCSX coils at the former Tokamak Fusion Test 

Reactor test cell. Most of the machine subassembly also 

will be performed here. Next year we will start building 

the vacuum vessel and the 18 modular coils that will be the 

heart of the machine itself. We will start building the three 

field-period subassemblies in 2005. Each will consist of six 

coils and one-third of the vacuum vessel. Final assembly 

will begin in 2006, with first plasma scheduled for June of 

2007. We expect NCSX to operate for about 10 years.

What are the roles of other U.S. fusion laboratories in 

the NCSX program? Which labs are involved? Foreign 

labs?

ORNL is our partner in the project. They have key leadership 

roles including responsibility for the design of the stellarator 

core itself. When the project moves into operation, ORNL 

will have significant responsibilities for management and 

Continued on page 4
PPPL NEWS • Summer 2003 Page 4

research. Other laboratories and universities, including 

foreign ones, will collaborate with us on NCSX research. 

Several have already expressed interest. It is too early to 

know exactly who will do what, but certainly diagnostics, 

divertors, plasma heating, and theoretical tools will be fruitful areas for collaboration. 

Starting next year, we will hold a series of national research 

forums, like those so successful for NSTX, for open discussions of the NCSX research program with the larger community. The input from these meetings will help determine what 

tools are needed and will enable our potential collaborators 

to plan for participation in the program.

A program advisory committee composed of fusion physicists 

from several U.S. and foreign institutions has served the 

project very well through the planning and design phases. 

It includes experts in all branches of plasma physics, both 

stellarator and non-stellarator people. It will focus on research planning issues when we get closer to operation to 

help guide the research program.

Tell us about the site preparations that are now underway 

at PPPL and about the space that will be dedicated to NCSX 

and its support systems.

NCSX will be located in the former PLT/PBX-M test cells, 

and the NCSX control room will be constructed in the area 

once occupied by the PLT and PBX-M control rooms. So 

there will be a significant modernization and upgrade of the 

C-Site area of PPPL, which in the 1960’s was the site of the 

Model-C Stellarator.

Currently, a crew led by PPPL’s Erik Perry is orchestrating 

the removal and preparation of the PLT/PBX-M areas. The 

old control rooms have been cleared out. Power supplies 

have been disconnected from PBX-M, and a decommissioning contractor has purchased PBX-M for scrap. Four of 

the old PBX-M poloidal field coils will be shipped to our 

NCSX partner, ORNL, for use on QPS. We expect that the 

test cell will be cleared by August. In 2006, following their 

fabrication in the TFTR test cell, NCSX’s three field-period 

subassemblies will be transported to C-Site, and assembly 

of the stellarator core will begin. ●

The group attending the NCSX Conceptual Design Review are, from left, Alex Pletzer, Art Grossman (UCSD), Don Monticello, Phil Heitzenroeder, Guoyong Fu, Mike Kalish, Ron Strykowsky, Long-Poe Ku, Gary Oliaro, Ed Lazarus (ORNL), Jim Lyon (ORNL), Martha Redi, Jim 

Chrzanowski, Hutch Neilson, Jerry Levine, Greg Pitonak (DOE), Brad Nelson (ORNL), Judy Malsbury, Dave Johnson, Neil Pomphrey, Raki 

Ramakrishnan, Chuck Finfgeld (DOE), Bob Simmons, Allan Reiman, Wayne Reierson, Harry Mynick, John Schmidt, Rob Goldston, Warren 

Marton (DOE), Mike Zarnstorff, Rich Hawryluk, and Irving Zatz.

The team members participating in the NCSX project are: (from PPPL) Bill Blanchard, Art Brooks, Tom Brown, Fred 

Dahlgren, Larry Dudek, H. M. Fan, Russ Feder, Eric Fredrickson, Guoyong Fu, Charlie Gentile, Geoff Gettelfinger, Rob 

Goldston, Pamela Hampton, Ron Hatcher, Rich Hawryluk, Phil Heitzenroeder, Stuart Hudson, Dave Johnson, Chang Jun, 

Mike Kalish, Long-Poe Ku, Henry Kugel, Doug Loesser, Jerry Levine, Frank Malinowski, Judy Malsbury, Dick Majeski, 

David Mikkelsen, Don Monticello, Lew Morris, Harry Mynick, Hutch Neilson, Gary Oliaro, Erik Perry, Alex Pletzer, 

Neil Pomphrey, Raki Ramakrishnan, Martha Redi, Wayne Reiersen, Allan Reiman, Joe Rushinski, Paul Rutherford, John 

Schmidt, Bob Simmons, Tim Stevenson, Brent Stratton, Ron Strykowsky, Hiro Takahashi, Al von Halle, Mike Viola, Mike 

Williams, Mike Zarnstorff, Irving Zatz; (From ORNL) Bob Benson, Lee Berry, Mike Cole, Paul Goranson, Steve Hirshman, Ed Lazarus, Jim Lyon, Stan Milora, Peter Mioduszewski, Brad Nelson, Larry Owen, Don Spong, Dennis Strickler, 

David Williamson; (Others) Allen Boozer (Columbia U.), Alexander Georgiyevskiy (consultant), Art Grossman (UCSD), 

Dave Hill (LLNL). ●

Continued from page 3
Page 5 PPPL NEWS • Summer 2003

Budding Young Scientists Exhibit Projects at PPPL

Area students, toting their winning science experiments, came to 

PPPL on April 25 for the Lab's annual Science Day Fair. The Science 

Fair honors the winners of PPPL's Corporate Awards, who were chosen among student exhibitors in March at the North Jersey Regional 

Science Fair at Raritan Valley Community College, and at the Greater 

Mercer Science and Engineering Fair at Rider University. The young 

scientists exhibited their work in the Lobby, which included topics 

such as the effect of temperature on the speed of light, creating 

static electricity, and robotic surveillance using appearance-based 

obstacle detection. Above, PPPL physicist Doug Darrow (left) talks 

to student exhibitor Meghan Kara McNulty about her project, "The 

Laser: Light, Optics, and Purity."

PPPL physicist and Nobel Laureate Russell Hulse (at right) hears 

about Kassandra Barone's project, "Bendhams Disks."

PPPL Hosts Area Students for Science Bowl

On March 1, PPPL hosted the U.S. Department of Energy's Regional Science Bowl competition that drew 29 teams from area high schools. 

At left, PPPL Deputy Director Rich Hawryluk (standing) serves as a science judge while two teams vie. At right, U.S. Congressman Rush 

Holt (far left) stands with the winning team, the Academy for the Advancement of Science and Technology in Bergen County.
PPPL NEWS • Summer 2003 Page 6

DeLooper Honored 

for Outreach

Awards

J

ohn DeLooper, Associate Director of External Affairs 

at PPPL, recently received the Department of Energy 

Distinguished Associate Award. DeLooper was honored 

for his “valuable coordination of countless education 

outreach activities and special events.” 

 In particular, DeLooper was cited for his efforts in 

coordinating the Snowmass Fusion Summer Study Workshops, which took place in Snowmass, Colorado, in 2002 

and 1999. At the most recent, about 300 leading scientists 

from the U.S. and international fusion community attended 

the two-week forum that assessed the major next steps in 

fusion energy science research.

 Above, N. Anne Davies, DOE’s Associate Director of 

Science for Fusion Energy Sciences, presents the award to 

DeLooper during a March DOE meeting in Maryland.●

Simmons Named 

Engineering Fellow

I

n recognition of his exceptional engineering achievements and contributions to 

the engineering profession, 

PPPL's Robert Simmons was 

recently elected a Fellow of 

the American Society of Mechanical Engineers (ASME) 

International.

 Simmons, the Systems 

Engineering Support Manager 

at PPPL for the National Compact Stellarator Experiment 

(NCSX), joined the Laboratory’s staff in 1989 as a 

project control manager. He has been actively involved 

in the operation and management of complex engineering projects and the development and implementation of 

project management systems for more than 35 years.

 Simmons received a bachelor’s degree from the Naval 

Academy in 1966 and a master’s in business administration 

from Ohio State University in 1975. Before coming to 

PPPL, he worked in private industry as a project manager 

for nuclear power plant services and served nine years 

on U.S. Navy nuclear submarines in various capacities, 

including as a supply officer, operations officer, and navigator. He retired from the Navy as a reserve captain in 

1991. Last year, Simmons received the first ASME Engineering and Technology Leadership Award, which has 

been named the Robert T. Simmons Leadership Award 

in his honor. ●

Robert Simmons

The U.S. Department of Energy’s (DOE’s) National 

Laboratories house world-class facilities where more 

than 30,000 scientists and engineers perform cutting-edge research spanning DOE’s science, energy, 

national security, and environmental quality missions. Interested in the latest achievements of the 

National Laboratories? Then visit the DOE Pulse 

at: http://www.ornl.gov/news/pulse/.

On June 26, PPPL’s Chris Ritter received a Service Award as President and Trustee of the Education 

Fund of Trenton, Inc., from the Trenton School District. 

The Education Fund is a non-profit corporation whose 

mission is to enhance the quality of educational programs 

in the Trenton Public Schools. ●

Ritter Awarded
Page 7 PPPL NEWS • Summer 2003

Local Officials Have Breakfast with Lab Director

PPPL Director Rob Goldston hosted a breakfast briefing for local government and school officials on June 

27. Sixteen state, county, municipal, 

and school representatives from the 

area attended. Goldston gave a talk 

about fusion and PPPL Deputy Director Rich Hawryluk guided a tour of 

some of the Lab’s experimental areas. 

At top, Goldston (standing) gives the 

presentation. At right, Hawryluk (far 

left) leads a tour of the National Spherical Torus Experiment (NSTX). ●
Page 8 PPPL NEWS • Summer 2003

Summer Students Abound at PPPL

Students from around the nation are at PPPL this summer — many to assist in the development of fusion energy 

— to conduct research and develop science curricula. 

The students are here through the National Undergraduate Fellowship Program (NUF), Science Undergraduate 

Laboratory Internships (SULI), and Pre-service Teachers 

(PST) programs. All programs are funded by the U.S. 

Department of Energy (DOE).

 The NUF program in Plasma Physics and Fusion 

Energy Sciences, administered by PPPL staff, provides 

a summer research experience to outstanding junior undergraduates at laboratories and universities nationwide. 

Twenty students were selected this year to conduct research 

in the disciplines that comprise the plasma sciences, in 

general, and fusion research, in particular. This year, six 

of the NUF students work with mentors at PPPL, while 

the remaining 14 students conduct their research at other 

laboratories.

 Through SULI, college students are placed in paid 

internships in science and engineering at any of several 

DOE facilities, with students working with scientists or 

engineers on projects related to the laboratories’ research 

programs. Seven SULI students chose PPPL to do their 

research this summer.

 Two students, one an undergraduate and the other 

a graduate student, are at PPPL this summer to develop 

science curricula through the PST program. The students 

are dedicated to teaching in the sciences. ●

At top, outside PPPL’s Lyman Spitzer Building, are many of this year’s 

summer students. Above, PST participant Riley O'Brien works at 

PPPL on her summer project, which includes writing a curriculum 

module with improved methods for teaching science. The module 

is for elementary and secondary teachers. O'Brien is also in the 

middle of the group picture.