Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Breakthrough in superconducting materials opens new path to fusion

11.11.2015

New high-temperature superconducting materials are also compatible with high magnetic fields

In fusion reactor designs, superconductors (which suffer no resistive power loss) are used to generate the magnetic fields that confine the 100 million degree C plasma.


Conceptual design of the ARC fusion reactor. About the same size as the currently operating JET tokamak in the United Kingdom, but with three times the magnetic field strength, ARC is sized to produce 500 MW of deuterium-tritium fueled fusion power.

Credit: Earl Marmar

While increasing magnetic field strength offers potential ways to improve reactor performance, conventional low-temperature superconductors suffer dramatic drops in current carrying ability at high magnetic fields. Now, the emergence of high-temperature superconductors that can also operate at high magnetic fields opens a new, lower-cost path to fusion energy.

A typical measure of fusion plasma performance is called "plasma beta," which is the ratio of plasma pressure to magnetic field pressure. Achieving a very high beta--generating the required plasma pressure with low magnetic field--could help reduce the cost of the superconducting magnets used in a fusion reactor.

For this reason, many visions of fusion reactors try to maximize plasma beta at moderate magnetic field strengths. Operation at higher beta, however, pushes the plasma up against many performance limits, making plasma stability a tricky business.

But plasma beta is not the only consideration. Another ratio, the size of the confined plasma compared to the ion gyroradius, also determines overall energy confinement and dictates plasma performance. (The ion gyroradius is the helical path ions are forced to follow in the magnetic field.)

Increasing magnetic field strength decreases the ion gyroradius, which allows a reduction in the size of the fusion device with no loss of performance. This approach also lowers beta and the plasma operates farther away from stability limits, in a "safe zone."

While scientists have explored both of these paths to improving performance, the recent development of the so-called "high-temperature superconductors" opens a window for much higher magnetic fields, as the critical currents do not degrade rapidly, even at magnetic field values of 30 Tesla or higher. So these should really be called high-temperature, high-magnetic-field superconductors.

For tokamak design, the field strength limits are primarily determined by the maximum allowable stresses in the structural components holding the magnet together, and not by the intrinsic limits of the superconductors.

Even the most aggressive tokamak designs with conventional superconductor technology are limited to about 6 Tesla on-axis toroidal magnetic fields. By nearly doubling magnetic field strength, to about 10 Tesla on-axis, conceptual designs indicate that a tokamak approximately the physical size of the world's largest currently operating tokamak, JET, would be capable of producing 500 MW of fusion power, and even net electricity (Figure 1).

High-temperature, high-magnetic-field superconductors can also make it possible to incorporate jointed magnetic coils into the reactor design, dramatically improving flexibility, and ultimately, maintainability for reactor systems.

While several physics and technology challenges remain to be solved, the world-wide experience from tokamak experiments provides the basis to support a new path of exploration into compact, power producing reactors using the newly available high-temperature, high-magnetic-field superconducting technology.

###

Contact: Earl Marmar, (617) 253-5455, marmar@psfc.mit.edu

Abstracts: JT2.00001 Considerations of the high magnetic field tokamak path on the approach to fusion energy
Session Session JT2: Tutorial: Considerations of the High Magnetic Field Tokamak Path on the Approach to Fusion Energy
2:00 PM-3:00 PM, Tuesday, November 17, 2015
Room: Chatham Ballroom C

Media Contact

Saralyn Stewart
stewart@physics.utexas.edu
512-694-2320

 @APSphysics

http://www.aps.org 

Saralyn Stewart | EurekAlert!

More articles from Physics and Astronomy:

nachricht Magnetic nano-imaging on a table top
20.04.2018 | Georg-August-Universität Göttingen

nachricht New record on squeezing light to one atom: Atomic Lego guides light below one nanometer
20.04.2018 | ICFO-The Institute of Photonic Sciences

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Spider silk key to new bone-fixing composite

University of Connecticut researchers have created a biodegradable composite made of silk fibers that can be used to repair broken load-bearing bones without the complications sometimes presented by other materials.

Repairing major load-bearing bones such as those in the leg can be a long and uncomfortable process.

Im Focus: Writing and deleting magnets with lasers

Study published in the journal ACS Applied Materials & Interfaces is the outcome of an international effort that included teams from Dresden and Berlin in Germany, and the US.

Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) together with colleagues from the Helmholtz-Zentrum Berlin (HZB) and the University of Virginia...

Im Focus: Gamma-ray flashes from plasma filaments

Novel highly efficient and brilliant gamma-ray source: Based on model calculations, physicists of the Max PIanck Institute for Nuclear Physics in Heidelberg propose a novel method for an efficient high-brilliance gamma-ray source. A giant collimated gamma-ray pulse is generated from the interaction of a dense ultra-relativistic electron beam with a thin solid conductor. Energetic gamma-rays are copiously produced as the electron beam splits into filaments while propagating across the conductor. The resulting gamma-ray energy and flux enable novel experiments in nuclear and fundamental physics.

The typical wavelength of light interacting with an object of the microcosm scales with the size of this object. For atoms, this ranges from visible light to...

Im Focus: Basel researchers succeed in cultivating cartilage from stem cells

Stable joint cartilage can be produced from adult stem cells originating from bone marrow. This is made possible by inducing specific molecular processes occurring during embryonic cartilage formation, as researchers from the University and University Hospital of Basel report in the scientific journal PNAS.

Certain mesenchymal stem/stromal cells from the bone marrow of adults are considered extremely promising for skeletal tissue regeneration. These adult stem...

Im Focus: Like a wedge in a hinge

Researchers lay groundwork to tailor drugs for new targets in cancer therapy

In the fight against cancer, scientists are developing new drugs to hit tumor cells at so far unused weak points. Such a “sore spot” is the protein complex...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

IWOLIA: A conference bringing together German Industrie 4.0 and French Industrie du Futur

09.04.2018 | Event News

 
Latest News

Magnetic nano-imaging on a table top

20.04.2018 | Physics and Astronomy

Start of work for the world's largest electric truck

20.04.2018 | Interdisciplinary Research

Atoms may hum a tune from grand cosmic symphony

20.04.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>