Is Nuclear Fusion Possible?

Nuclear fusion is the process of combining light atomic nuclei, such as hydrogen isotopes, to release an immense amount of energy. This process powers the sun and other stars, and has the potential to provide a clean and abundant source of energy for Earth. However, turning fusion into a practical energy source has proven to be a significant challenge.

The Fundamentals of Nuclear Fusion

The Fusion Process

The main process that powers the sun and stars is the fusion of two hydrogen atoms to make helium. When such light atomic nuclei combine, they release an immense amount of energy. This energy release is due to the fact that the mass of the resulting helium nucleus is slightly less than the combined mass of the two hydrogen nuclei. The difference in mass is converted into energy according to Einstein’s famous equation, E = mc^2.

The Electrostatic Barrier

However, the challenge lies in the fact that these nuclei have positive electrical charges, and they repel one another. It takes tremendous pressures and temperatures to overcome this electrostatic barrier and get the nuclei to merge. The required temperatures are on the order of 100 million kelvins, several times hotter than the center of the sun.

Plasma Confinement

If scientists can contain the fuel for fusion—a plasma mixture of deuterium and tritium, two heavy isotopes of hydrogen—the energy released in the reaction can make it self-sustaining. But the key challenge is how to bottle a plasma at such extreme temperatures and pressures.

Measuring Fusion Performance

is nuclear fusion possible

Energy Confinement Time (τE)

One of the key plasma performance measures is the energy confinement time (τE), which measures how well the magnetic field insulates the plasma. The larger τE, the more effective a fusion reactor will be as a net source of power.

Power Balance Equation

The power balance per unit volume in a fusion reactor is given by the equation:

P = Pext + Pα – PL

– Pext is the external heating power density from microwaves or beams
– Pα is the power density produced by fusion reactions
– PL is the power density lost by turbulent transport of heat across the magnetic field

Energy Gain (Q)

The energy gain is defined by the ratio:

Q = Pα/PL

At sufficient pressure, the plasma is entirely self-heated and Pext = 0; this is termed ignition. High gain (Q > 1) is essential for commercial fusion as supplying external heating reduces the net output and complicates reactor design.

Fusion Product (PτE) and Temperature (T)

The ‘fusion product’, PτE, and the temperature, T, determine the energy gain of the fusion device. In the temperature range 100–200 million degrees Celsius, ignition occurs when PτE > 20 (P in atmospheres and τE in seconds).

Approaches to Achieving Fusion

Magnetic Confinement

There are several approaches to achieving fusion, including magnetic confinement and inertial confinement. The most popular design for magnetic confinement is the tokamak, which uses a toroidal (or doughnut-shaped) container to hold the plasma in a magnetic bottle formed by strong magnetic fields.

Inertial Confinement

In inertial confinement fusion, the fuel is compressed and heated by the impact of intense laser or particle beams, rather than by magnetic fields. This approach aims to achieve the necessary high temperatures and pressures for fusion to occur before the fuel disperses.

The ITER Project

The ITER project, an international collaboration, is currently building the world’s largest tokamak, with the goal of demonstrating the scientific and technical feasibility of fusion energy for peaceful purposes.

Challenges and Prospects

Turning fusion into a practical energy source requires overcoming significant scientific and engineering challenges, such as:

  1. Containing and heating a plasma to high temperatures and pressures
  2. Developing materials that can withstand the extreme conditions inside a fusion reactor
  3. Achieving the necessary energy confinement time and gain for self-sustaining fusion reactions

Despite these challenges, progress is being made, and an orderly fusion development programme could lead to a prototype fusion power station putting electricity into the grid within 30 years, with commercial fusion power following some ten or more years later.


In summary, nuclear fusion is possible and has the potential to provide a clean and abundant source of energy. However, the scientific and engineering challenges involved in realizing this potential are significant and will require sustained research and development efforts. With continued progress, fusion could become a reality in the coming decades, revolutionizing the way we produce energy and addressing the global energy and climate challenges.


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