A Collaborative National Center for Fusion & Plasma Research



  •  In March, Lyman Spitzer, Jr. proposes to the Atomic Energy Commission (AEC) the construction of a magnetic plasma device to study controlled fusion.

  • On July 1, the AEC approves funding. The research effort becomes part of Project Matterhorn, a classified project studying the hydrogen bomb. Spitzer heads the controlled thermonuclear research section. A former rabbit hutch becomes the initial home for the Project.


  • Princeton's first research device is the Model A stellarator. Experiments compare plasma confinement in the figure-8 geometry with confinement in a simple racetrack geometry. Basic idea for Ion Cyclotron Resonance Heating (ICRH) of the plasma is set forth.


  • Ideal magnetohydrodynamic (MHD) theory is used to formulate a variational energy principle. The principle provides a powerful method to analyze the gross MHD stability of plasmas in different magnetic confinement configurations.


  • The B-65 stellarator begins operation in November. It is frequently operated without energizing its helical field coils, in a geometry now known as a tokamak. Use of a toroidal-field divertor leads to marked improvement in plasma purity and higher temperatures.


  • Controlled thermonuclear research is declassified. In September, Princeton exhibits a working stellarator (B-2) in Geneva, Switzerland, at the United Nations' Second International Conference on the Peaceful Uses of Atomic Energy. Click here for a stellarator article by Dr. R. A. Ellis, Jr.

  • The Model B-3, the last figure-8 stellarator built at Princeton, begins operation. It is used intensively during the 1960s to study plasma transport.

  • Project Matterhorn's first linear device, L-1, begins operation for the study of basic plasma physics.


  • The first Princeton doctoral degree in plasma physics is awarded. Since then, more than 260 students have received doctorates-- many have gone on to be scientific leaders in the field.


  • Melvin B. Gottlieb succeeds Lyman Spitzer, Jr. as head of Project Matterhorn. On February 1, Project Matterhorn is renamed the Princeton Plasma Physics Laboratory (PPPL). The change signified recognition of the fact that long-range physics research lay ahead.


  • Model C Stellarator begins operation in March following a 4-1/2-year design and construction effort. The largest of a series of stellarators, it is a test-bed for intense studies of plasma transport. With the coming of the Model C, the figure-8 stellarators of the 1950s surrendered their center-stage position.


  • PPPL's first program to use neutral-beam injection for plasma heating is proposed. During the next three decades, neutral-beam heating will play a key role in the progress toward the attainment of the plasma conditions required for the production of significant amounts of fusion power.


  • The Linear Multipole-1 (LM-1) begins operation. LM-1 experiments are the first to investigate the magnetic well concept. These experiments confirm theoretical hypotheses.


  • In July, it is decided to convert the Model C Stellarator to a tokamak. Model C ceases operation on December 20. Its conversion to the Symmetric Tokamak will take only four months.


  • On May 1, the first United States' tokamak experiments begin on the Symmetric Tokamak (ST) at PPPL.


  • Early experimental results from the ST show favorable confinement. Tokamak research now begins in earnest. The Floating Multipole-1 (FM-1) begins operation in August. Experiments on FM-1 pioneer the concept of a poloidal divertor.


  • The Adiabatic Toroidal Compressor (ATC) begins operation in May. It is the first tokamak without a copper liner and with an air core transformer, both representing bold innovative design changes. ATC successfully demonstrates the use of compressional heating of a tokamak plasma.


  • First neutral-beam heating experiments in a tokamak are conducted in ATC.


  • Congress approves the Tokamak Fusion Test Reactor (TFTR) Project. TFTR will be the first magnetic fusion device in the world to conduct experiments with a 50/50 mixture of deuterium and tritium, the fuels likely to be used in fusion power plants of the 21st Century.


  • The Princeton Large Torus (PLT) begins operation on December 20. PLT experiments are expected "...to give a clear indication whether the tokamak concept plus auxiliary heating can form a basis for a future fusion reactor."


  • Groundbreaking ceremonies for TFTR take place in October. Many international, national, and local dignitaries attend.


  • In July, PLT sets a world record for ion temperatures of 60 million degrees C using neutral-beam heating. For the first time, ion temperatures exceed the theoretical threshold for ignition in a tokamak device.

  • In August, Russian physicist Katerina Razumova presented Mel Gottlieb with a Russian Firebird in recognition of PLT's world record temperatures. Russian mythology says that whoever captures the Firebird and wins from it a blazing feather can use that feather to realize his or her dreams.


  • Harold P. Furth succeeds Melvin Gottlieb as director of PPPL.

  • PLT produces the first tokamak discharge in which the plasma current is driven entirely by lower-hybrid radio-frequency waves.


  • The Advanced Concepts Torus-1 (ACT-1) demonstrates ion-Bernstein wave heating of a tokamak plasma for the first time. Smaller research devices like ACT-1 are used to investigate new concepts, perform basic plasma physics experiments, and are especially well suited for research projects by doctoral candidates.

  • TFTR produces first plasma on December 24. Nearly nine years have elapsed since conceptual design study in 1974 to first plasma discharge.


  • PLT uses ion-cyclotron radio-frequency heating to produce ion temperatures of 60 million degrees C, a record for this technique.

  • PPPL's Soft X-ray Laser demonstrates X-ray lasing at 18.2 nm in a magnetically confined laser-produced plasma. Applications for the Soft X-ray Laser include the study of live biological specimens and micro-lithography. Several other near-term practical uses of plasma science and technology are studied at PPPL during the 1980s and 1990s.


  • Neutral-beam heating experiments on TFTR produce world record ion temperatures of approximately 200 million degrees C-- more than ten times the temperature at the center of the sun. Levels of plasma temperature and heat confinement exceed the basic objectives specified for TFTR.

  • TFTR produces the first demonstration of tokamak bootstrap current driven by pressure gradients within the plasma itself, rather than by external means.

  • A new enhanced-confinement plasma regime, called "supershots," is discovered in TFTR where peaked density profiles obtained with neutral-beam heating lead to a reduction in energy leakage by a factor of 2 to 3.


  • The magnetohydrodynamic model is extended to include kinetic effects, which are essential for the stability of high-temperature tokamak plasmas.

  • The Princeton Beta Experiment-Modification (PBX-M), successor to the PDX, achieves a PPPL record beta of 6.8%. Beta is a measure of the effectiveness of the magnetic field in containing a high-pressure plasma. Values achieved are in the range of those anticipated in a commercial fusion reactor.


  • The fourth state of matter (a plasma, a hot ionizing gas) can be used to produce vast amounts of electricity, but first it must be controlled. In the 1950s, scientists used helical magnetic fields to bottle a plasma in a configuration known as a tokamak that insulated it from the surrounding walls. But they needed a way to discern how induced electrical currents in the plasma modify the magnetic field that guides the plasma and protects the surrounding walls. A landmark 1989 paper explained how to measure the magnetic field by interpreting visible light emitted by atoms injected into the plasma using accelerated hydrogen beams. Today, these measurements allow scientists to precisely tailor the magnetic field to improve plasma confinement and maximize fusion performance.

    F.M. Levinton, R.J. Fonck, G.M. Gammel, R. Kaita, H.W. Kugel, E.T. Powell, and D.W. Roberts, "Magnetic field pitch-angle measurements in the PBX-M tokamak using the motional Stark effectExternal link." Physical Review Letters 63, 2060 (1989). [DOI: 10.1103/PhysRevLett.63.2060]. Subscription required: contact your local librarian for access. (Image credit: Claire Ballweg, DOE)

    (from "40 Years of Research Milestones", the DOE 40th Anniversary - The Office of Science Presents: Research Milestones Over The Past 40 Years 1977-2017,  on the DOE Office of Science website: https://science.energy.gov/news/doe-science-at-40/)


  • TFTR sets world records for ion temperature -- 400 million degrees C -- and fusion power production -- 60,000 watts -- in deuterium plasmas.


  • Ronald C. Davidson becomes the fourth director of PPPL.


  • PPPL physicist Russell Hulse shares Nobel Prize for co-discovering the first binary pulsar while a graduate student at the University of Massachusetts at Amherst.

  • In December, TFTR achieves a world-record 6.3 million watts of fusion power in the world's first magnetic fusion experiments with a 50/50 mixture of deuterium and tritium.


  • In May, TFTR produces a new world record of 9.2 million watts of fusion power in 50/50 deuterium-tritium experiments.

  • In June, confined alpha particles are successfully detected in the TFTR plasma core and do not drive significant plasma instabilities, nor do they accumulate in the plasma. These results are very promising for the eventual production of self-sustained plasmas. In November, TFTR produces a new world record of 10.7 million watts of fusion power.

  • A challenge with fueling a fusion reactor is reliably getting the fusion reaction to occur. In this landmark 1994 paper, scientists described a high-powered mixture of fusion fuels that allowed the Tokamak Fusion Test ReactorExternal link (TFTR) to shatter the world-record for fusion energy when it generated 6 million watts of power. This milestone was achieved using a 50/50 blend of two hydrogen isotopes; deuterium and tritium. The work was instrumental in building the scientific basis for ITERExternal link, a tokamak-based reactor to be fueled by deuterium and tritium and designed to test the viability of fusion as an energy source.

    J.D. Strachan, et al., "Fusion power production from TFTR plasmas fueled with deuterium and tritiumExternal link." Physical Review Letters 72, 3526 (1994). [DOI: 10.1103/PhysRevLett.72.3526]. Subscription required: contact your local librarian for access. (Image credit: Princeton Plasma Physics Laboratory)

    (from "40 Years of Research Milestones", the DOE 40th Anniversary - The Office of Science Presents: Research Milestones Over The Past 40 Years 1977-2017,  on the DOE Office of Science website: https://science.energy.gov/news/doe-science-at-40/)


  • TFTR produces a new world-record ion temperature of 510 million degrees C in February.

  • In April, indications of alpha particle heating are identified during TFTR deuterium-tritium experiments. This bodes well for the attainment of self-heated or "burning" plasmas in future devices.

  • In July, scientists increase TFTR's central density up to three-fold and reduce particle leakage by a factor of 50 using the enhanced reversed-shear mode, discovered on TFTR. This could eventually lead to smaller, more economical fusion power plants.

  • In July, engineering design begins for the National Spherical Torus Experiment (NSTX).

  • In October, the Magnetic Reconnection Experiment (MRX) begins operation. Experiments on MRX will study the physics of magnetic reconnection-- the topological breaking and reconnection of magnetic field lines in plasmas.


  • In July, Robert J. Goldston becomes the fifth director of the Princeton Plasma Physics Laboratory.

  • The Tokamak Fusion Test Reactor completes its last series of experiments on April 4 following nearly 15 years of operation.


  • NSTX creates "first plasma" on February 12, following a national design and construction effort completed 10 weeks ahead of schedule.


  • NSTX produces a 1.0-million-ampere full-design plasma current, nine months ahead of schedule, followed by the production of 1.4 million amperes in 2001.


  • The safe disassembly and removal of TFTR, a three-year effort, is completed on schedule and under budget, freeing up this advanced facility for future work.

  • A combination of neutral-beam-driven and self-generated "bootstrap current" in NSTX provides about 60 percent of the total plasma current, thereby relaxing the need for induction to sustain the current.

  • PPPL engineers develop the Miniature Integrated Nuclear Detection System (MINDS) a portable system that can detect radionuclides for anti-terrorism.


  • NSTX achieves a record toroidal beta of 40%, three times the values in conventional tokamaks. Beta relates to fusion power production economics.

  • The CDX-U device demonstrates that liquid lithium surfaces facing or contacting the plasma result in a dramatic improvement in plasma parameters.


  • NSTX researchers develop methods to sustain high beta by employing a set of small magnetic coils, controlled by feedback, to counteract the growth of certain instabilities.

  • Experiments on PPPL's Magnetic Reconnection Experiment (MRX) identified the Hall effects in the reconnection layer, explaining fast reconnection in collision free plasmas.


  • A 160-thousand-ampere plasma current is initiated in NSTX without induction from its central solenoid. This world record is attained using a technique known as Coaxial Helicity Injection.


  • The evaporation of lithium coatings on plasma facing components in NSTX is shown to improve plasma confinement and to prevent instabilities called Edge-Localized Modes.

  • MRX group identified the electron diffusion region demonstrating the importance of two-fluid effects in the reconnection layer.


  • First-of-a-kind high spatial resolution measurements on NSTX confirm the existence of a long-theorized form of plasma turbulence driven by variation of the electron temperature across the plasma. Tiny swirls of turbulence in the plasma may be one cause of the long-standing mystery of electron heat loss.

  • The Lithium Tokamak Experiment (LTX) produces its first plasma. The new device will continue CDX-U's promising work on the use of pure lithium metal on plasma facing components.


  • New PPPL management team arrives: Stewart Prager, the sixth PPPL director; Adam Cohen, deputy director for operations; and Michael Zarnstorff, deputy director for research.


  • The Lithium Tokamak Experiment (LTX) demonstrates fourfold increase in pulse duration and sevenfold increase in plasma current compared with discharges without lithium wall coating.


  • PPPL hosts international workshop on roadmapping the next steps for development of magnetic fusion energy. Event leads to annual roadmapping workshops under the auspices of the International Atomic Energy Agency. 

  • PPPL begins $94 million upgrade of the National Spherical Torus Experiment. More...


  • PPPL opens nanotechnology laboratory as future resource for institutions and industries around the world. More...

  • PPPL and Princeton University team with Germany’s Max Planck Institute for Plasma Physics to create Max Planck Princeton Research Center for Plasma Physics. More...

  • PPPL wins R&D 100 Award. A group of scientists, including a team at PPPL, is honored for aiding in the development of a device representing a key advance for fusion energy. More...

  • PPPL receives federal Sustainability Award from the U.S. Department of Energy for reducing overall greenhouse gas emissions 48 percent since 2008, far exceeding mandated goals. More...


  • PPPL teams with South Korea to develop conceptual design for South Korea’s K-DEMO reactor. More...

  • A.J. Stewart Smith, Princeton University’s first dean for research, becomes vice president for PPPL. More...

  • Christopher L. Eisgruber named Princeton University’s 20th president. Shirley M. Tilghman retires after 12 years in office. More...

  • New Jersey Department of Environmental Protection recognizes PPPL as top facility in New Jersey for environmental stewardship. More...


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    PPPL engineers install a new 70-ton neutral beam machine and larger center stack on NSTX-U. More...


  • The largest project at PPPL today is an advanced nuclear fusion reactor–or tokamak–called the National Spherical Torus Experiment (NSTX). Researchers from over 30 U.S. institutions and 11 other countries are collaborating in this effort. More...


  • U.S. Department of Energy Secretary Ernest Moniz dedicated the most powerful spherical torus fusion facility in the world on Friday, May 20, 2016. The $94-million upgrade to the National Spherical Torus Experiment (NSTX-U), funded by the DOE Office of Science, is a spherical tokamak fusion device that explores the creation of high-performance plasmas at 100-million degree temperatures many times hotter than the core of the sun. More...

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