Scientists observe key process behind cosmic magnetic fields for first time

A discovery by a team of scientists, including academics from a Welsh university, has shed new light on one of the most fundamental energy‑conversion processes in the cosmos.

The team observed a natural cosmic dynamo operating in near‑Earth space for the first time, bringing them significantly closer to understanding how magnetic fields are created in the universe.

Much like the way in which generators convert kinetic energy into electricity, cosmic dynamos work by transforming the movement of electrically conducting gas or plasma into magnetic fields.

The discovery was made by an international research team involving physicists from Aberystwyth University, led by the Space Research Institute of the Austrian Academy of Sciences.

Observation 

The dynamos are believed to power the magnetic environments of planets, stars, and galaxies, yet directly observing them in space has long remained out of reach.

However, the new study, published in Nature Communications, identified clear evidence of a small‑scale dynamo inside Earth’s magnetosheath, the boundary where solar wind slams into Earth’s magnetic field.

Constantly compressed, stirred, and reshaped by solar wind pressure, the magnetosheath provides the only known natural environment where scientists can directly probe dynamo behaviour in a collisionless space plasma.

This discovery brings scientists significantly closer to understanding how magnetic fields are generated and maintained throughout the cosmos – an essential process that helps shape the behaviour of the entire Universe.

‘Extraordinary result’

Dr Owen Roberts, from the Department of Physics at Aberystwyth University, said: “This is an extraordinary result. For the first time, we can see a natural plasma dynamo in action right on our cosmic doorstep.

“The measurements we take will help bridge the gap between laboratory experiments, computer simulations, and the real behaviour of space plasmas.

“Understanding how dynamo action works is essential for explaining the evolution of magnetic fields in planets, stars, and galaxies.”

The breakthrough was made possible using NASA’s Magnetospheric Multiscale (MMS) mission, a fleet of four identical spacecraft flying in a precise pyramid‑like formation.

The unique configuration enabled researchers to capture simultaneous measurements of plasma flows and magnetic fields in three dimensions.

With this data, the team observed magnetic fields being stretched and folded by rapid plasma motions and regions where magnetic strength weakened and curved back on itself.

Dynamo theory 

They also saw zones where magnetic intensity grew, exactly as dynamo theory predicts, and plasma instabilities that allow the dynamo to operate even in the absence of particle collisions.

These signatures match decades of theoretical predictions and computer simulations but have never been observed so clearly in space until now.

Dr Roberts from Aberystwyth University added: “The four NASA spacecraft give us a 3D view of the turbulence, allowing us to observe magnetic fields stretching, twisting, and growing exactly as theory predicts.

“Being able to witness these mechanisms in action transforms what was once purely theoretical into something we can measure and test. It’s a breakthrough that will reshape how we study magnetic fields throughout the cosmos.”