Scientists Unravel Mystery of Neutron Star's Powerful Magnetic Fields

Neutron stars are extraordinarily dense stellar bodies that are created when massive stars collapse. Yet while these stars host some of the strongest magnetic fields in the universe, some of them are more strongly magnetized than others. Now, scientists have found out why this is.

Previous theoretical studies have suggested that the magnetic field of a neutron star should break into smaller loops and dissipate as the star ages. This particular phenomenon is known as "turbulent cascade." Yet there exist several middle-aged neutron stars that have strong magnetic fields, which seem to indicate that this particular theory isn't correct.

In order to better understand how magnetic fields change as a neutron star ages, the researchers conducted a series of computer simulations. These simulations showed that the magnetic field evolves rapidly at first, but that the evolution took a surprising turn later on. No matter what the magnetic field looked like when the neutron star was "born," it took on a particular structure and its evolution dramatically slowed later on.

"A cascade in a magnetic field is akin to what happens when you add cream to your coffee and stir it: the cream rapidly gets broken up into pieces and mixes into the coffee," said Andrew Cumming, one of the researchers, in a news release. "The original prediction was that neutron star crusts would do the same to their magnetic fields; so if you could walk around on the surface with a compass trying to walk towards magnetic north, you would end up walking around in random directions. Instead, we find in these new simulations that the magnetic field actually remains quite simple in structure-as if the cream refused to mix into the coffee-and you could, indeed, use a compass to navigate around on the surface of the star."

The findings reveal a bit more about neutron stars. More specifically, it reveals a bit more about these massive magnetic fields, which could inform future studies about the physics of our universe.

The findings are published in the journal Physical Review Letters.