Of Interest archive

Among the most feared events in space physics are solar eruptions, massive explosions that hurl millions of tons of plasma gas and radiation into space. These outbursts can be deadly: if the first moon-landing mission had encountered one, the intense radiation could have been fatal to the astronauts. And when eruptions reach the magnetic field that surrounds the Earth, the contact can create geomagnetic storms that disrupt cell phone service, damage satellites and knock out power grids.

NASA is eager to know when an eruption is coming and when what looks like the start of an outburst is just a false alarm. Knowing the difference could affect the timing of future space missions such as journeys to Mars, and show when steps to protect satellites, power systems and other equipment need to be taken.

(Photo NASA)

Read the whole article on the PPPL website.

Momentum is building on the MAST Upgrade project at the Culham Centre for Fusion Energy (CCFE) in the UK.

When completed, the upgrade of the Mega Amp Spherical Tokamak (MAST) will enable scientists to test the spherical tokamak design as a candidate for a Component Test Facility that will trial technology and materials in advance of the next-step machine; add to the knowledge base for ITER on key plasma physics issues; and test a high-power exhaust system known as a Super-X divertor.

The final phase of assembly will take place in 2016.

See the three-minute video on the CCFE website.

Scientists at the US Department of Energy's Princeton Plasma Physics Laboratory (PPPL) have produced self-consistent computer simulations that capture the evolution of an electric current inside fusion plasma without using a central electromagnet, or solenoid.

The simulations of the process, known as non-inductive current ramp-up, were performed using TRANSP, the gold-standard code developed at PPPL. The results were published in October 2015 in Nuclear Fusion. The research was supported by the DOE Office of Science.

In traditional donut-shaped tokamaks, a large solenoid runs down the centre of the reactor. By varying the electrical current in the solenoid scientists induce a current in the plasma. This current starts up the plasma and creates a second magnetic field that completes the forces that hold the hot, charged gas together.

But spherical tokamaks, a compact variety of fusion reactor that produces high plasma pressure with relatively low magnetic fields, have little room for solenoids. Spherical tokamaks look like cored apples and have a smaller central hole for the solenoid than conventional tokamaks do. Physicists, therefore, have been trying to find alternative methods for producing the current that starts the plasma and completes the magnetic field in spherical tokamaks. 

One such method is known as coaxial helicity injection (CHI). During CHI, researchers switch on an electric coil that runs beneath the tokamak. Above this coil is a gap that opens into the tokamak's vacuum vessel and circles the tokamak's floor. The switched-on electrical current produces a magnetic field that connects metal plates on either side of the gap.

Read more on the PPPL website.

The 2015 roundup of news from the US ITER Project Office is now available online.

US ITER achieved a number of project "firsts" for delivery and fabrication over the last year. Deliveries to the ITER site included the first nuclear grade hardware (drain tanks) and the first highly exceptional load shipment to ITER (a 90-ton electrical transformer). The US also supplied the first plant components installed at the ITER site (a total of four transformers). On the fabrication side, US ITER shipped its first production toroidal field conductor to the coil manufacturer in Europe and has begun fabrication of the first central solenoid module.

Read all the news here.

Fusion in Europe is a regular magazine on the progress of fusion research published by the EUROfusion consortium. In the December 2015 issue, the magazine takes a look at ongoing preparations for the deuterium-tritium campaign at JET, at the research planned on the upgraded spherical tokamaks MAST (UK) and NSTX (US), and at topical program news from fusion laboratories all over Europe.

Read the latest Fusion in Europe here.

For the close of the year, EUROfusion—the European Consortium for the Development of Fusion Energy—is highlighting 24 cutting-edge technologies that have either benefited from, or are the by-products of, fusion research.

Superconducting magnets, low-activation heat-resistant materials, high-tech filters, sophisticated computer codes ... work being carried out around the world on fusion science and technology is pushing known technologies to new levels or breaking new ground for the benefit of many other sectors and, ultimately, society at large.

Follow the Spinoff Advent Calendar on EUROfusion's website.

Members of MIT's Plasma Science and Fusion Center (PSFC) community are cheering the start of a long-anticipated physics experiment at the Max Planck Institute for Plasma Physics in Greifswald, Germany. Two teams of PSFC researchers are collaborating on the Wendelstein 7-X device, the world's largest fusion experiment designed in the stellarator line of magnetic confinement fusion devices.

The PSFC has significant experience with a different configuration of magnetic confinement, having spent decades designing and running the Alcator series of high-magnetic-field tokamak experiments — the Alcator C-Mod device, located on campus, is the latest in that series. There are many similarities between the two designs, however. 

Both the tokamak and the stellarator seek to harness the energy released from the fusion of hydrogen isotopes to provide clean and safe electrical power. Both use helical (spiraling) magnetic fields to contain the hot plasma fuel in a donut-shaped chamber. In a tokamak, this field is generated both by external electromagnets and a large electrical current that is driven in the plasma itself. Driving and sustaining this plasma current, and its impact on stability and transport of energy and particles, is a major focus of the research at MIT.

The stellarator concept takes a different approach. First invented by the noted astrophysicist and fusion pioneer Lyman Spitzer of Princeton University in 1950, the stellarator provides the entire helical field through external electromagnets formed in highly complex and twisted shapes. 

Future experiments at W7-X will address the role that plasma turbulence plays in limiting overall performance, and PSFC researchers are working with the W7-X group to investigate this. One PSFC team — principal research scientist Jim Terry and postdoctoral researcher Seung-Gyou Baek — will develop a fast camera system for viewing light emitted from the plasma, and will make important measurements of turbulence near the edge of the plasma. The other team — physics professor Miklos Porkolab and staff scientist Eric Edlund — will develop a specialized interferometer for imaging density fluctuations deep in the hot plasma core. The issues surrounding turbulence are important in stellarators, as they are in tokamaks, since turbulence moves heat and particles across the confining magnetic field faster than would otherwise occur. Both teams expect to have first measurements during the 2017 experimental campaign.

Read the original article on PSFC's website here.

The Russian Domestic Agency for ITER reports that two shipments recently left factories in Saint Petersburg and Podolsk for the ITER Project.

The first shipment contains correction coil busbars—the components that connect magnet coils to their power sources—as well as flexible links for busbar interconnections. These components were transported by truck (pictured) from the Efremov Institute (NIIEFA) in Saint Petersburg directly to the ITER site. The fabrication and supply of switching equipment, busbars and energy-absorbing resistors for the power supply and the protection of the ITER superconducting magnetic system add up to the most expensive, and one of the most complicated, systems falling within the scope of in-kind procurement from Russia (25 systems in all). In accordance with the busbar Procurement Arrangement, NIIEFA will manufacture and ship approximately 5.4 km of busbars with a total weight exceeding 500 tons.

In the second shipment, four lengths of poloidal field superconductor (two unit lengths of 720 metres and two of 414 metres) were loaded onto trucks at the Cable Institute (JSC VNIIKP) in Podolsk for delivery to the European jacketing line at Criotec (Chivasso, Italy). The conductors are destined for the ITER poloidal field coil magnet system.

-- Alexander Petrov, ITER Russia

On 4 December the Programme Manager of EUROfusion, Tony Donné, visited ITER and spoke to staff in the ITER auditorium.

EUROfusion is a consortium of 29 research organisations and universities from 26 European countries plus Switzerland that is collaborating to achieve Europe's Fusion Roadmap, which outlines the most efficient way to realize fusion electricity by 2050. ITER is the key facility on the road to fusion energy, and Professor Donné stressed in his talk that everything possible must be done to support ITER construction, optimize ITER operation and ensure minimal delay to the next-phase device, DEMO.

Professor Donné also advocated the extension of the European tokamak JET under an international regime in support of ITER. The prolonged use of JET as a risk-mitigation device for ITER and for the training of a generation of scientists, engineers and technicians for ITER could give the world fusion community access to deuterium-tritium plasmas approximately 10 years before ITER.

Read more about EUROfusion, Europe's Fusion Roadmap, and JET.

The aim of the WEST project is to turn the Tore Supra tokamak (France) into a test bed for ITER, with an actively cooled ITER-like tungstendivertor.

Component installation is underway. The latest WEST Newsletter (#11) reports on the most recent milestone: the installation of the divertor coil casings. Two stainless steel rings constituting the housing for the conductor windings are now assembled and positioned inside the vacuum vessel at their nominal position. The building of the coil winding can now begin.

(Photo Christophe Roux CEA-IRFM)

Read all the latest from WEST in Newsletter 11 here.

An 18-month development program to prototype remote handling tooling for the ITER fusion device was demonstrated on 26 and 27 October as part of collaboration between the European Domestic Agency for ITER and the Culham Centre for Fusion Energy (CCFE) in the UK.

Representatives from the ITER Organization, the European agency, Assystem UK, and AMEC Foster Wheeler were at Culham to see a fully remote deployment of prototype remote pipe cutting and welding tooling developed by Culham's RACE (Remote Applications in Challenging Environments).

Under a grant from the European Domestic Agency, RACE and CCFE's Engineering Implementation Department have produced a set of prototype tools intended for eventual use maintaining the neutral beam heating systems at ITER. Up to now, remote cutting and welding of process piping to the required codes, and under the challenging conditions of the ITER tokamak, had not been demonstrated, and is one of the higher risk areas across the ITER remote maintenance strategy.

ITER will rely on remote handling for maintenance operations where space and/or environmental conditions in the machine do not allow manual intervention. Interconnected components, pipes, cranes and tooling will all need to be routinely repaired and maintained with millimetric accuracy.

Read the full reports of the event on the European Domestic Agency and CCFE websites.