How Scientists Are Edging Closer to Making Fusion Energy a Reality

The dynamics inside fusion reactors are so complex that the walls sometimes melt when ferociously hot high-speed plasma becomes unstable. Now, the Max Planck Institute for Plasma Physics and the Vienna University of Technology have solved a major fusion problem, bringing us closer to creating an infinite source of energy.
nuclear fusion

Fusion power is a type of power generation that uses fusion reactions to produce electricity. These reactions occur in a fusion reactor, which uses a magnetic field to confine and heat a plasma until conditions are suitable for fusion.  

Fusion reactions are similar to those that power the sun. In both cases, hydrogen atoms are combined to form helium, a process that releases a tremendous amount of energy, which can be used to generate electricity.

Fusion power plants have the potential to provide sustainable energy, resolving our long-standing energy problems. This is the primary reason why so many scientists around the world are researching this power source.


How does Fusion power generation work?

Plasmas must be heated to 180 million degrees Fahrenheit / 100 million degrees Celsius in reactors for the method to work. Magnetic fields encircle the plasma, preventing the reactor’s walls from melting. The shell that forms around the plasma can only function because the shell’s outermost centimeters, known as the magnetically formed plasma edge, are exceptionally well insulated.

Inspiration from the stars

Fusion is the source of energy that powers stars, and it has the potential to be used as a clean and powerful source of energy here on Earth. A toroidal tokamak fusion reactor is a magnetic confinement device that controls plasma behavior to create fusion. Toroidal tokamak fusion reactors typically use a doughnut-shaped chamber with a magnetic field that runs through its center. The magnetic field is used to confine the plasma within the chamber and to control its behavior. The purpose of a toroidal tokamak fusion reactor is to create conditions conducive to fusion, which is the process by which two atoms join together to form a new, heavier atom.


Plasma instabilities known as edge localized modes (ELMs) are sudden, large-amplitude disruptions of the plasma edge that occur in tokamaks. ELMs are a type of edge-mode instability and are the most active and disruptive type of edge instability in tokamaks. ELMs are a major source of heat and particle losses in tokamaks and can damage the plasma-facing components of the tokamak.


The problem with this method of enclosing the plasma’s sun-level heat is that there are plasma instabilities known as edge localized modes in that region (ELMs). During the fusion reaction, ELMs are common. During an ELM, energetic plasma particles may strike the reactor’s wall, potentially damaging it.

Protecting the reactor’s walls

After many trials of different methods, the researchers discovered that a plan previously abandoned was the best mode of operation the Max Planck Institute for Plasma Physics and the Vienna University of Technology have found a method to control Type-I ELM plasma instabilities. If they become large enough, Type-I ELM plasma instabilities can melt the walls of fusion devices. 

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The research focuses on reducing the destructive large Type-I ELM plasma instabilities that could damage the reactor’s walls and instead allow numerous minor instabilities that do not endanger the reactor’s walls.


Elisabeth Wolfrum, professor at TU Wien and research group leader at IPP in Garching, Germany, said their team’s work represents a breakthrough in understanding the occurrence and prevention of large Type I ELMs.

Wolfrum believes that the operation regime their team proposes is the most promising scenario for future fusion power plant plasmas.

A new design for toroidal tokamak fusion reactors

To reduce destructive large Type-I ELM plasma instabilities, the existing model of toroidal tokamak fusion reactors has had to be redesigned. The dynamic of the reactor is complicated, but it adapts to particle motion which is affected by plasma density, temperature, and magnetic field. The way these parameters are chosen determines how the reactor will operate. When smaller plasma particles hit the walls or the reactor, the reactor takes on a triangular shape with rounded corners instead of a round shape, but the shape is far less damaged than with a large ELM.

The Electric Tokamak
The Electric Tokamak by Pierre.alexandre.gourdain under CC BY-SA 4.0

Georg Harrer, the paper’s lead author, provides a layperson’s explanation. He compares the new reactor design to a cooking pot with a lid where the water begins to boil. If the pressure rises further, the lid will lift and rattle violently due to the escaping steam, but if the lid is tilted slightly, steam can escape continuously while the lid remains stable and does not rattle.

The work of the Max Planck Institute for Plasma Physics and the Vienna University of Technology is the first step towards the goal of generating a continuous fusion reaction, which, if successful, might lead to the creation of an unending energy source. In the event that the concepts developed during this research come to fruition, fusion energy may turn out to be more applicable than other options proposed for the production of energy, such as solutions based on space-based solar power (which involves beaming energy down from space) or geothermal energy (funneling energy up from the depths of the Earth).