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The international conference PLASMA-2013 was organized by the Local Organizing Committee created at IPPLM. The Polish Physical Society was the co-organizer of this venture. More than 140 participants from various countries declared the participation in PLASMA-2013. The International Scientific Committee invited more than 20 recognized specialists from Poland and abroad to give an oral presentation. The Ministry of Science and Higher Education supported the organization of the conference with a special subsidy. Several Polish and foreign private companies sponsored the conference presenting their scientific equipment. More detailed information is available on http://plasma2013.ipplm.pl.

The PLASMA conferences have been organized since 1993 mainly in Poland. In 2007 the conference took place in Germany and in 2010 – in France. The main goal of the next PLASMA conferences is to create a scientific forum for detailed discussion and evaluation of progress in research of plasma physics and plasma technology as well as thermonuclear fusion. The majority of presented works is performed in the framework of the international cooperation, most frequently covered by the European programmes. The conference has been considered an important international scientific event of exceptional importance for scientific communities in Eastern and Western Europe. It facilitates the meetings of young scientists with experienced researchers from renowned centres in Poland and abroad.

Let us provide the reader with some statistics. The total number of participants (including 11 IPPLM scientists) amounted to 131 persons from 24 countries. The invited lectures were presented by 18 distinguished researchers and oral presentations (2 of them by IPPLM scientists - P. Gąsior and M. Kubkowska) were delivered by 24 participants. Moreover, 90 posters (10 from IPPLM) were put on display and discussed. The conference participants took part in a trip to Wilanów Palace, which was built for the Polish king Jan III Sobieski in the last quarter of the 17th century, and enjoyed it immensely.

The research and implementation of plasma in different branches of science and technology are being intensively developed around the world. An important goal of hot plasma research is to harness the controlled thermonuclear fusion for the future production of safe and applicable energy for people and the environment. Low-temperature plasma finds various technological applications, among others in electronics, space technology and modification of material characteristics.

Several research centres in Poland deal with plasma and thermonuclear research within close international collaboration. Those include: Institute of Plasma Physics and Laser Microfusion, National Centre for Nuclear Research, PAS Institute of Nuclear Physics, PAS Space Research Centre, PAS Institute of Fluid-Flow Machinery, Opole University and several other scientific communities in other universities and institutes. IPPLM coordinates works regarding thermonuclear fusion in tokamaks and stellarators in the framework of the Association EURATOM-IPPLM and laser fusion within the European HiPER project.

“It’s a bittersweet moment for us because we are saying goodbye to the old machine but at the same time, we are already looking forward to the new one,” said the CCFE spokesman Nick Holloway.

“At 4pm today, we will run the last plasmas and within minutes after that, engineers will move in to shut down the tokamak for the next 18 months. By Monday, the roof beams in the MAST machine area will have been taken off before the 25-tonne MAST vessel will be lifted on a big crane and moved to the assembly hall.”

The £30m upgrade is set to make MAST (the Mega Ampere Spherical Tokamak), a cutting edge facility. It will increase its power and enable testing technologies that will improve the knowledge base needed for the construction of ITER, but also to test systems for the DEMO prototype fusion power plant.

“To take fusion forward to ITER and through to commercial power, we need to keep improving our research facilities. In 2015, CCFE will have a machine that we and our collaborators from around the world can use to explore exciting new areas of plasma physics and test innovative concepts for fusion technology. We can’t wait,” said Dr Brian Lloyd, Head of CCFE Experiments Department.

One of the key technologies the upgraded MAST will be equipped with is the Super-X divertor, an innovative high-power exhaust system that will reduce the power loads from particles leaving the plasma.

The divertor is an exhaust system at the bottom of the fusion chamber, through which waste rejected from the plasma leaves the reactor. The particles being exhausted are extremely energetic, resulting in extreme power loads on in this part of the reactor. The idea of Super-X is to steer the particles along a longer exhaust path, allowing them to cool down and spreading them over a larger area, so that the power loads on materials are significantly reduced. 

“This technology could actually pave the way towards future fusion power stations. It will be the very first time anyone will be using this technology,” Holloway said.

Since 1999, MAST, an innovative spherical tokamak, a successor of UK’s earlier venture called START, has created over 24,000 man-made stars, providing a wealth of data. The knowledge gathered during the MAST experiments has helped advance understanding in many key areas including plasma instabilities and start-up methods.

The spherical concept that MAST inherited from START, has proven over the years to be more efficient than the conventional toroidal design, adopted by JET and ITER.

MAST has originally been commissioned by Euroatom and the UK Atomic Energy Agency, the current upgrade, however, is funded by the Engineering and Physical Sciences Research Council.

Apart from the Super-X divertor, the tokamak will receive a new centre column, better divertor coils, and a cryopump and power supplies that will provide pulse lengths up to ten times that of the existing machine.

As Holloway said, the MAST engineers and physicist are definitely not going on a 18-month vacation. They will be busy analysing the data the tokamak has provided previosly and will have to prepare new experiments for the improved machine.

“There will also be a lot of work developing the new systems and also a lot of theoretical work to do that will be put to practice later,” Holloway concluded.

VIDEO: A fusion experiment inside the MAST device

Source: Engineering and Technology Magazine

Andy Warhol elevated the humble banana to an icon of pop art, with his 1967 album cover for the band the Velvet Underground. Proving its versatility, the banana is now also an icon of magnetically confined fusion research, thanks to the curious shapes traced out by particles zigzagging around the tokamak; every student of fusion physics has to learn about banana orbits.

Often the food analogies applied to tokamaks centre around doughnuts, due to the shape of magnetic field that confines the hot fusion plasma. But as one delves deeper into the complicated world of gyrokinetics, the simplistic doughnut transforms into a more complex banana orbit in a journey from the ideal to the real world.

Simple spirals

In the simplistic, doughnut-shaped magnetic field, charged particles are constrained to spiral along the magnetic field by one of the Universe’s strangest phenomena, the Lorentz force, which governs the interaction of charged particles with a magnetic field. This interaction happens when the particle is moving at an angle to the magnetic field. Bizarrely the field neither attracts nor repels the particle, but applies to it a sideways force, at right angles to both the direction of travel, and the magnetic field lines. For example, a particle travelling horizontally through a vertical magnetic field might experience a force to turn left (depending on the respective polarities of the particle’s charge and the magnetic field). Having turned left, it’s still travelling horizontally – at right angles to the vertical field – so it continues to feel a force to the left. And so it turns some more, and more, and more – trapped in a never-ending circle.

If the original angle of travel of the particle was not exactly at right angles to the magnetic field (in the example above, perhaps travelling slightly upwards) then it will still circulate around the field line, but moving along it as well, tracing out a spiral path. The closer the particle’s path is to parallel with the magnetic field, (in our example vertical) the more stretched out the spiral is – but always following the field line.

Banana realities

The premise of the tokamak is to construct a doughnut shaped magnetic field and then the plasma particles will merrily spiral around it for ever. Enter an uncomfortable reality of geometry; as you can see in the main image above, the magnets are closer together in the centre of the torus (the hole of the doughnut) than they are around the outside. This means the magnetic field is not uniform: it is stronger in the inside part of the ring.

This means that the helical path the particle follows is not symmetrical. A tighter turn on the high field (inner) side of the line, and looser on the outside leads to a drift either upwards or downwards (depending on the direction of rotation). This is the beginning of our banana orbit , as shown in the projected cross-section at the left-hand side of the figure. As an example, let’s follow a particle on the inside of the banana halfway up, gradually creeping downwards to trace the banana’s inner edge.

If this downward drift continued unchecked, the particles would escape the plasma all too soon. Countering this drift was one of the master strokes of tokamak design, via the inclusion of a solenoid in the hole of the doughnut. Driving a changing current through this solenoid drives a plasma current around the doughnut, serving to generate a field at right angles to the ring of magnet coils. This additional right-angled field gives a twist to the doughnut’s magnetic field, thereby circulating the particles that would otherwise drift away back into the middle. This gives the banana its curve.

The pointy end of the banana

As the particles circulate around into the higher field area their progress along the  field line slows, because the field lines are no longer parallel, but converge slightly as the field increases. In fact for particles moving slowly along the field but rapidly around it – i.e. in more tightly wound spirals – this field convergence is enough to stop them altogether, and bounce them back towards to where they came from. This defines the apex of the banana orbit.

However, the particles do not retrace their steps exactly, because of the continuous drifting below the field line. Instead they trace the outer part of the banana’s outline, back to the middle and then continue downwards to its lower apex. However, beyond the centreline – the part of the banana orbit the furthest from the centre – our example particle’s downward drift now brings it back towards the centre of the plasma. Its path traces the lower half of the banana’s outline, to the lower apex in the higher magnetic field and then back up to its original starting place. In addition, the magnetic field line angle is different on the outer part of the banana from that on the inner part, producing the zig-zag shown in the figure.

A tangled tale

The cross section of this orbit is banana shaped, although the reality for the many particles in the plasma is much more of a tangle… the initial speed and angle of the particle can radically vary the exact number and distribution of bounces, and indeed whether any particle stays within the plasma or escapes.

The shape can change too, close to the centre of the plasma the cross section of the orbit is more like a potato, or a kidney bean; the other particles that do not bounce – called the passing particles – follow orbits that are just slightly outwardly displaced with respect to the magnetic field lines.

Put them all together, it all begins to merge into one giant bowl of spaghetti. Endlessly complex, but delicious nonetheless!

Thanks for all the help on this article and image, from Sean Conroy for orbit data, Dave Cooper for data processing, Russell Perry and Chad Heys for graphics flair, and Tom Todd for technical discussions.

SOurce: EFDA

When you hear the term nuclear energy, images of Fukushima or Three Mile Island may come to mind. But harnessing nuclear power isn't limited to the reactors that we currently use, which rely on nuclear fission. Energy can also be harnessed from fusion.

"Nuclear fusion is the energy that powers the sun and stars," Mike Mauel, professor of applied physics at Columbia University, told CBSNews.com. "It takes hydrogen gas, heating up to millions of degrees, and brings the atoms together to release energy and make helium."

Instead of splitting an atom's nucleus, like in fission, nuclear fusion is the process of bringing together two atomic nuclei to form a new nucleus. And there is no need for dangerous chemical elements like uranium or plutonium -- easing the fears of nuclear proliferation. Energy derived from fusion is appealing because very few natural resources are required to create fuel.

"The fuel for fusion basically comes from sea water. Every bottle of water that we drink has heavy water -- deuterium -- inside. Enough that's equivalent to a whole barrel of oil," Mauel says.

According to the U.S. Energy Information Administration(EIA), approximately 68 percent of the country's electricity in 2011 was generated by coal, natural gas, petroleum and oil. The next highest energy source was nuclear energy at about 20 percent. About 13 percent was contributed by renewable sources, like solar, hydropower, wind, geothermal and biomass.

A United Nations panel of scientists has reportedly agreed, with near certainty, that humans have a direct influence on climate change. The organization is expected to release its findings in an upcoming annual report.

"It is extremely likely that human influence on climate caused more than half of the observed increase in global average surface temperature from 1951 to 2010," says a draft of the report, obtained by the New York Times. "There is high confidence that this has warmed the ocean, melted snow and ice, raised global mean sea level and changed some climate extremes in the second half of the 20th century." 

or the first time in recorded history, the amount of carbon dioxide in the air could rise to 400 parts per million(ppm) -- it's currently just over 390 ppm.

According to the Scripps Institution of Oceanography at the University of California, San Diego, CO2 levels hadn't surpassed 300 ppm in 800,000 years.

The race to replace fossil fuels with a sustainable replacement includes advancements in solar, wind, biomass and nuclear technology. Scientists believe that energy created from nuclear fusion is not only inevitable, but the only option that makes sense as a long-term solution.

"Many people who work in fusion power look 50 to 100 years in to the future, and we say 'what else can provide sustainable clean energy source for thousands of years on a large scale,' and fusion's one of the only ways to do that," Mauel says.

"I think that advances that we're making in solar power, wind power, clean coal technology, nuclear power -- all that is going to help us get through the next 50 years. But after that, we have to have fusion power."

In France, the International Thermonuclear Experimental Reactor (ITER) is the world's largest science experiment, and aims to prove that fusion can be achieved on a mass scale. The European Union, United States, China, South Korea, Japan, India and Russia have agreed to invest in building a reactor that can conduct experiments in burning plasma.

"ITER solves the technical problems," Dr. Ned Sauthoff, director of the U.S. ITER Project, told CBSNews.com. "Then industries in each country decide whether it will build reactors."

Sauthoff says that we know fusion has been done, but not in a large enough quantity to provide electricity on a mass scale. It is estimated that ITER will produce 500 megawatts of power for about 50 megawatts put in.

Progress doesn't come cheap. In the United States, Sauthoff says it could cost $10 billion to build the first fusion reactor.

"There are a lot of cost reductions that will come in the future," Sauthoff says. "Right we have an R&D system with lots of knobs and lots of dials. And that's expensive."

Mauel believes that while it's important to continue investing in renewable energy in the interim, it's only a matter of time before fusion energy will be a viable option for producing electricity.

"The fusion power will be ready in the second half of this century, and I think that's when we're going to need it most," Mauel says.

Source: CBS NEWS

Scientists at JET, the world’s largest fusion energy research facility, have been deliberately melting parts of their own machine as they test materials for the fusion reactors of the future. These apparent acts of scientific vandalism are actually courageous experiments which have yielded valuable information for JET’s successor – the huge international ITER project being built in the south of France.

The experiments were requested by ITER, which is currently assessing what material should be used for its plasma-facing wall. To achieve fusion, gas is heated to over one hundred million degrees, at which temperature it becomes a plasma, similar to the sun. Plasma is held inside a magnetic chamber known as a tokamak. Of particular concern to researchers are bursts of turbulence on the edge of the plasma similar to solar flares, which can momentarily inflict on to small areas of the tokamak wall heat loads far greater than a blow torch.

JET scientists have been astonished by the machine’s faultless performance during the recent tests.

“There was a slight worry we would see uncontrolled, firework-like splashes of molten metal,” said Dr Gilles Arnoux, one of the scientific coordinators of the experiment, “and that might affect subsequent experiments. But it was a smooth melt; the plasma didn’t seem to notice. I was surprised at how little impact it had.”

The tests at JET involved subjecting a small area of deliberately misaligned tungsten wall tile to regulated bursts of turbulent events. The peak temperature of the tile during the transient bursts was slowly increased until it exceeded tungsten’s melting point, 3422 degrees Celsius, to assess what effect molten tungsten might have on the operation of the plasma. In particular, it was feared that a melt event might contaminate the hydrogen-based plasma with tungsten and lead to a disruption – an uncontrolled energy dump from the plasma – which could lead to further surface melting in a fusion experiment as large as ITER.

Instead, as shown in the picture, the molten tungsten moved smoothly to one end of the tile and formed a droplet, that grew with each additional plasma pulse. Curiously the molten metal did not run downwards – a result of the magnetic forces inside the tokamak – and, to the scientists’ relief, moved away from the hottest part of the plasma rather than being swept back into the exposed area. Subsequent experiments were performed without any interruption to proceedings.

Joining the JET team in the control room was the leader of ITER’s Divertor and Plasma Wall Interactions section, Dr Richard Pitts, who has been involved throughout the planning of the experiment.

Dr Pitts said: “It has been a great success and has achieved what it set out to do: to demonstrate that repetitive, fast transient heat pulses pushing tungsten over the melt threshold for just a millisecond or two each time, do not drive melt splashing nor do they appear to have any observable effect on the core plasma. It seems that we can broadly understand what we have seen on the basis of complex computer simulations describing the melt dynamics and thus our confidence is increased in the extrapolations we make for the behaviour to expect on ITER, which use the same computer codes. These results are extremely significant for the choice which ITER is preparing to make regarding the use of tungsten.”

Despite the early optimism much analysis remains to be done. The full story will not be known until mid 2014, when JET’s current run of experiments concludes and the melted tile can be removed and analysed.

Source: EFDA