As a child, I witnessed innumerable incidents of load shedding in Delhi, especially during summers. This meant no electricity at home and studying by candlelight for hours. Even today 24/7 power supply remains a dream that is unfulfilled. Just imagine, there are around 396 million people with no access to electricity in India! Around 75% of the world population is living in developing countries with energy demands that are expected to surpass that of developed nations in the next 50 years. My big question is: “How do we tackle this energy crisis?” We will be running out of non-renewable resources in the next 40 to 80 years. But, coal, oil and natural gas currently supply most of the world’s energy.

THE DILEMMA OF CHOICE

Inside the stellarator Wendelstein 7-X. Picture: Christophe Roux/EUROfusion

Inside the stellarator Wendelstein 7-X. Picture: Christophe Roux/EUROfusion

The general scepticism about nuclear energy is well known. Like most countries, India has also witnessed raging controversy regarding the suitability of nuclear power as the solution to ever growing energy requirements. I too was drawn into this debate and thus developed a strong desire to contribute something towards the promotion of clean and abundant energy. It engendered in me a deep interest in nuclear physics and engineering. It was only during my master’s studies that I understood in-depth the prospect of employing fusion power as an almost inexhaustible source of energy for future generations. Now, I am proud to work at one of the most developed fusion experiments in this world: the stellarator Wendelstein 7-X (W 7-X).

CONFINEMENT IS KEY

Fusion reactions take place at high temperatures of around 10 keV (~100 million Kelvin) where the fuel is in a fully ionised state, also called plasma. The particles have a large thermal velocity with a tendency to escape from the machine. Hence, some method of confinement of particles is essential. Magnetic field confinement using high powered magnets is one of the solutions. Tokamaks and stellarators, two types of fusion experiments, are both based on this concept.

THE COMEBACK OF STELLARATORS – WENDELSTEIN 7-X

In the past, research into stellarators has been overshadowed by interest in the other concept, the tokamak. However, recent advances in computational power and engineering expertise have revived it. So, the inauguration of Wendelstein 7-X (W7-X), the world’s newest stellarator, has put stellarator research back on the fusion table.

See also the article “A snowflake for fusion?” by Carrie Beadle.

A recent publication in Nature Communication, by Prof Thomas Sunn “from my institute”, the Max Planck Institute for Plasma Physics, highlights the success achieved in W7-X. Sunn Pedersen discussed how he and his colleagues managed to tackle the challenges.

A LIKELY SAVIOUR: CONNECTION LENGTH

Picture: private

Picture: private

The main obstacle in reaching high powerdensity in fusion devices is the limited capability of the divertors. Divertors are the ashtrays of fusion experiments and need to withstand immense heat and particle loads.
My present goal is to develop of special magnetic configurations that should help to manage the heat flux. They will be tested in an operational campaign in W7-X. This should further assist us in comprehending the impact on the exhaust physics in a stellarator. Once the riddle of tackling the tremendous power exhaust from fusion plasma has been solved, we will have moved one large step closer to a fusion power plant.

THE SILVER LINING: NUCLEAR FUSION

The previous operation phase of W7-X has concluded in March 2016 and delivered promising results. We found parameters, for example, for plasma temperatures and densities, that enhance the performance of a stellarator plasma, exceeding predicted values from simulations. There is, of course, still a lot of research that must be done before nuclear fusion becomes a viable commercial option. Nevertheless, I feel like I am participating in the creation of the future solution for the demanding energy needs of the world. Fusion will, I hope, one day create energy for everybody.

TOKAMAKS vs STELLARATORS

info iconTokamaks are the most well developed reactor type due to their simple flat magnetic coil design. They have an induced electric current that confines particles on a helical path, but this current also means pulsed operation and results in unwanted instabilities. Stellarators have a complicated twisted coil design, which has been made possible thanks to modern computer modelling. These twisted coils produce a natural helical path thus avoiding the current instabilities and resulting in a much desired steady-state operation.

Clear

authorbox_Priyanjana-SinhaI am a PhD student, but also a science enthusiast with a passion for writing. I believe that nuclear fusion undeniably holds the key to solving the current global energycrisis. EUROfusion presents a perfect platform for young researchers like me to speak out and dispel the misconceptions as well as raising awareness about nuclear fusion amongst the general public.


Priyanjana Sinha
(25) from India is currently based at: Greifswald, Germany. (Picture: private)