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An international team of scientists has modeled the formation and evolution of the strongest magnetic fields in the universe.

Led by scientists from Newcastle University, University of Leeds and France, the paper was in the journal Nature Astronomy. The researchers identified the Tayler-Spruit dynamo caused by the fall back of supernova material as a mechanism leading to the formation of low-field magnetars. This new work solves the mystery of low-field magnetar formation, which has puzzled scientists since low-field magnetar discovery in 2010.

The team used advanced numerical simulations to model the magneto-thermal evolution of these stars, finding that a specific dynamo process within the proto-neutron star can generate these weaker magnetic fields.

Investigating complicated magnetic fields of neutron stars

Study lead author, Dr. Andrei Igoshev, Research Fellow at Newcastle University's School of Mathematics, Statistics and Â鶹ÒùÔºics, said, "Neutron stars are born in supernova explosions. Most external layers of massive stars are removed during the supernova, but some material falls back, making the neutron star spin faster. Researchers show that this process plays a very important role in the formation of a magnetic field via the Tayler-Spruit dynamo mechanism.

"This mechanism was suggested theoretically nearly a quarter century ago, but it was only recently reproduced using computer simulations. The magnetic field formed via this mechanism is very complicated with the internal field inside the star, which is much stronger than the external."

Magnetars are known to have enormous magnetic fields which are hundreds of trillions times stronger than the Earth's magnetic fields. Due to these fields, magnetars are bright and variable sources of X-ray radiation. Some of the less magnetized stars also have similar X-ray emission. These less magnetized stars are known as low-field magnetars. Dynamo is a mechanism which converts plasma motion into magnetic fields.

Dr. Igoshev is establishing a new research group at Newcastle University to further investigate the complicated magnetic fields of neutron stars.