Subscribe options

Select your newsletters:


Please enter your email address:

@

News & Media

Latest ITER Newsline

  • A world in itself

    From a height of some 50 metres, you have the entire ITER worksite at your feet. The long rectangle of the Diagnostics Building stands out in the centre, with [...]

    Read more

  • US completes toroidal field deliveries for ITER

    The US Domestic Agency achieved a major milestone in February by completing the delivery of all US-supplied toroidal field conductor to the European toroidal fi [...]

    Read more

  • Thin diagnostic coils to be fitted into giant magnets

    Last week was marked by the first delivery of diagnostic components—Continuous External Rogowski (CER) coils—from the European Domestic Agency to the ITER Organ [...]

    Read more

  • Addressing the challenge of plasma disruptions

    Plasma disruptions are fast events in tokamak plasmas that lead to the complete loss of the thermal and magnetic energy stored in the plasma. The plasma control [...]

    Read more

  • Blending (almost) seamlessly into the landscape

    Located in the foothills of the French Pre-Alps, the ITER installation blends almost seamlessly into the landscape. The architects' choice ofmirror-like steel c [...]

    Read more

Of Interest

See archived articles

NSTX upgrade to enhance fusion physics database

A researcher takes an upward view of the interior of NSTX, shown with the centre column. Copyright for all three photos: Princeton Plasma Physics Lab. (Click to view larger version...)
A researcher takes an upward view of the interior of NSTX, shown with the centre column. Copyright for all three photos: Princeton Plasma Physics Lab.
The Princeton Plasma Physics Laboratory (PPPL) has received approval from the US Department of Energy to upgrade its major test facility, the National Spherical Torus Experiment (NSTX). The three-year project, worth USD 94 million, is part of PPPL's mission to chart an attractive course for the development of nuclear fusion as a clean, safe and abundant fuel for generating electricity.

"The US fusion program places increasing emphasis on fusion materials science, and as part of that long-term vision, is presently considering moving toward a fusion nuclear science facility (FNSF)," explains Jonathan Menard, the NSTX program director. "Its objective is to develop the experimental database for all fusion reactor internals and, in parallel with ITER, provide the basis for DEMO." (For more information, see a recent  presentation by Dr. Edmund Synakowski, Associate Director, Office of Science, for Fusion Energy Sciences.)

 (Click to view larger version...)
"Both standard aspect ratio and low aspect ratio 'spherical' tokamaks are being considered for an FNSF device, and NSTX in the USA and MAST in the UK are the largest spherical tokamaks in the program worldwide. The spherical tokamak (ST) has the potential to provide a smaller and more maintainable FNSF, but many physics and technical issues remain for the ST. The recently begun upgrade of NSTX (and upcoming upgrade of MAST) will help address and resolve these remaining issues for the ST." 

The NSTX Upgrade will include the doubling of the reactor's
magnetic field to 1 tesla, the doubling of its plasma current to 2 million amperes, the doubling of its beam heating power from 5 MW to 10 MW, and a quintupling of the pulse-length from 1 s to 5 s. "This enhancement will provide access to reduced collisionality (higher temperature) to allow the study of the plasma transport and stability properties much closer to FSNF conditions," says Menard. "The new second neutral beam system that will provide the increased heating power is aimed more tangentially to increase the current drive efficiency and controllability, and this should enable access to fully non-inductive operation. Fully non-inductive current drive is essential for steady-state operation of a tokamak or ST-based FNSF to provide continuous operation and high neutron fluence. The same new Neutral Beam Injection (NBI)system is also predicted to be much better absorbed at low plasma current and will enable tests of non-inductive plasma current ramp-up—a critical need for ST designs that do not incorporate a central solenoid."

Inside the NSTX test cell: the apple-shaped fusion experiment includes exterior vertical red magnetic coils and horizontal blue magnetic coils. The rectangular steel box to the left of the machine contains the neutral beam system for heating plasma. (Click to view larger version...)
Inside the NSTX test cell: the apple-shaped fusion experiment includes exterior vertical red magnetic coils and horizontal blue magnetic coils. The rectangular steel box to the left of the machine contains the neutral beam system for heating plasma.
"The NSTX Upgrade (NSTX-U) will also explore high-flux-expansion 'snowflake' divertors, a novel magnetic divertor named for its shape, as well as liquid lithium as potential divertor power and particle control solutions for FNSF and beyond. All of the above enhanced research capabilities of the NSTX Upgrade also address key research needs for DEMO—independent of aspect ratio. Lastly, the lower collisionality plasmas and overall expanded operating capabilities of the NSTX Upgrade (NSTX-U) facility will enhance support of ITER physics studies and ITPA joint experiments as we approach ITER operation. For example, the new NBI system and higher field will enable NSTX-U to modify the fast-ion distribution function and the drive for fast-ion instabilities, improving our ability to understand fast-ion confinement for ITER burning plasmas. As another example, NSTX-U will be able to investigate rotation damping and transport changes from 3D magnetic fields at reduced collisionality to support improved understanding of ELM control using 3D fields on ITER."

Click here to read the related story on the PPPL website.


return to the latest published articles