Nuclear fusion, A science fiction or a reality?

Who doesn’t love Tony Stark in the movie Iron man? Who himself build an ‘arc reactor’ that powers the popular ‘Suite’ in the movie scenes? Now the point is where did the idea come from? The idea is an old or rather fundamental one. This is the only process by which starts to continue to live for millions of years. The quest for nuclear fusion started back in 1926 when British astrophysicist Arthur Eddington suggested that stars draw their energy from the fusion of hydrogen into helium. To replicate the fusion process in the Earth, scientists from the Soviet Union devised a way in which the thermonuclear reaction could be confined into a magnetic field. They called it ‘magnetic confinement fusion device’, the ‘tokamak’. So, What is ‘tokamak’?

The iron man wearing a fictional Fusion device 'arc reactor' in his chest
Pic courtesy: pixabay

What is nuclear fusion?

To answer the question, we must understand the way nuclear Fusion happens at the core of every star. There exists a very strong repulsive force between two or more atomic nuclei, but somehow if they are managed to fuse, an enormous amount of energy is generated which radiates in form of heat and light energy that we see and feel every daytime. Now the question is how they are going to fuse? Well, naturally in the core of stars, due to the heavy temperature, the atomic nuclei start to get a velocity near to the speed of light, that velocity helps them to overcome nuclear repulsion. For example, if 4 natural hydrogen atoms get fused it generates a Helium-4 (4He2). But what is strange is that the mass of a single Helium atom is 99.2% of 4 Hydrogen atoms before fusion. This indicates the 0.8% mass of the Hydrogen atoms has been converted into pure energy according to famous Einstein’s relation E = mc2, where m is the energy equivalent mass (0.8% here). So, a very tiny mass could give us an unimaginable amount of energy without generating any harmful isotopes as by-products unlike Its brother nasty ‘Nuclear Fission’ does. To get a glimpse of what amount of energy is generated one can refer to the 1st fusion bomb ‘Ivy Mike’ detonated by the US in 1952. Moreover, fusion generates heavier elements from lighter atoms, which is also responsible for the generation of heavier elements in the universe. In that aspect, we are also proof of nuclear fusion.

4 Hydrogen atoms are fused together to generate Helium atom inside the sun
pic courtesy: Wikipedia

How to replicate natural fusion in the Earth?

Nuclear fusion can give us the ultimate source of energy no doubt without many impacts in terms of by-products that it generates. If it has commercially become available, would be the most important treasure trove for humanity. One of the ways is to create ‘sun-like environment in the earth’. Which is done by confining a very hot plasma within a very strong magnetic field. What does it mean? It means the orange color that we see in the sun is the plasma that is one of the 4th states of matter that is generated when a nuclear fusion reaction happens inside the sun. Plasma is a stream of ionized particles, also being ions, they can be controlled by magnetic fields. But creating a plasma in natural earthly conditions is not going to work. For that, some special magnetic coils are required. When a current is passed through a magnetic coil it generates a magnetic field that we have studied in school days. Let us bring our imagination on step further and create a magnetic toroid, and concentrate inside the toroid where the magnetic field is strongest. This is the place where a super-hot plasma can be confined. That’s why every nuclear fusion experiment ridiculously complex and large.  

There is a video that describes the fusion process in a detailed manner, consider visiting the link:

Trials for nuclear fusion:

By 1950s, researchers started looking at possibilities of replicating the process of nuclear fusion on Earth. And in 1950 the tokamak was invented. This was followed, by Lyman Spitzer's concept for the stellarator in 1951. The stellarator concept dominated fusion research throughout the 1950s but lost its way when the experimental research on tokamak systems showed that the tokamak was a more efficient concept. Before the 1950s, U.S., UK, and USSR kept fusion research secret, However, by the mid-1950s administrators and scientists alike were convinced that controlled fusion research had no military applications, and in particular had nothing to do with the development of thermonuclear weapons. It was becoming clear by 1970 that attaining fusion energy would be one of science's greatest challenges and collaboration might be key to meeting the challenge. In 1973 European countries came together and began design work on the Joint European Torus, JET. First, worldwide collaboration took place, as a result of Reagan–Gorbachev initiative at Geneva Summit in 1985 with the equal participation of the Soviet Union, the European Atomic Energy Community, the United States, and Japan. The project began with the name of the International Thermonuclear Experimental Reactor (ITER). Later on, China, South Korea, and India (in 2005) became members of the ITER project. In the same year (2005), it was officially announced that ITER would be built in the European Union in Saint-Paul-Les-Durance, some 35 km north of Aix-en-Provence in southern France. Although the construction of the ITER tokamak complex started in 2013 it is expected to be completed by 2025, Initial plasma experiments are scheduled to begin in 2025, with full deuterium-tritium fusion experiments starting in 2035.

The ITER nuclear fusion project, pic courtesy: EUROfusion, 

India’s contribution to fusion research:

The research and development in thermonuclear fusion are lead by the Institute for Plasma Research (IPR), an autonomous R & D organization under the authority of the Department of Atomic Energy (DAE) near west banks of river Sabarmati in Gujarat. Under IPR two ‘tokamak’ machine is operating, they are ‘ADITYA’ & ‘Steady State Tokamak (SST) – 1’. Both of them are operating towards the stable & sustained generation of plasma, which is extremely important for the fusion process.

Also, IPR is providing the cryostat, a 30-meter diameter, equally tall stainless-steel vessel which envelops the entire basic systems of the tokamak and is a vacuum-tight container in the ITER project located in France. India is one of the countries is going to provide 9% funding of the total ITER project which is expected to start producing plasma by 2025.

Completion of Manufacturing of In-Wall Shield for ITER
pic courtesy:  http://dae.gov.in/node/1390

Conclusion:

Worldwide research of fusion has been started, most importantly some private organizations are also involved in finding a way for commercially viable nuclear fusion reactors. In terms of status, most of the organization has created plasma but it can’t sustain much to provide a space for actual fusion. As a result, the efficiency of the process is not good. To have a better future every country has to cut down carbon emissions to 0% within 1 or 2 decades. Otherwise, the way Earth is warming up it will not be favorable for us. On a different note, the planetary journeys will only be possible if we can construct a successful fusion device. Which is under the intermediate stage of research and development. It has to evolve much more before any fusion device comes commercially. If not, ‘star war’s’ starships will remain science fiction.