A team of astrophysicists from the Max Planck Institute for Astrophysics in Garching, Germany, and the University of Chicago, have performed experiments that reveal how the magnetic fields of extremely powerful magnetars are generated. Magnetars are a rare type of neutron star that harbors the strongest magnetic fields known in the universe. They are born in supernova explosions, the cataclysmic death of massive stars. The experiments show that the magnetic field in magnetars is generated by a powerful dynamo driven by the rapid rotation of the neutron star and its intense magnetic field. The results of the experiments are published in the journal Science.

Magnetars are a type of neutron star, the collapsed cores of massive stars that have exploded as supernovae. Neutron stars are extremely dense objects, with a mass of about 1.4 times that of the Sun but only a diameter of about 20 kilometers. Magnetars are a special class of neutron stars that possess extremely strong magnetic fields, with strengths ranging from 10^14 to 10^16 Gauss. This is about a trillion times stronger than the magnetic field of Earth.

The origin of the magnetic field in magnetars is not well understood. One possibility is that the field is generated by a dynamo process, similar to the one that generates the magnetic field of the Sun and Earth. In this process, the rotation of the neutron star induces electric currents in the electrically conductive plasma that fills its interior. These currents then create a magnetic field, which in turn reinforces the rotation of the star.

The experiments performed by the team of astrophysicists provide evidence for the dynamo mechanism in magnetars. The experiments were performed using a powerful laser to create a plasma that mimics the conditions inside a neutron star. The laser was focused onto a small target, creating a hot spot with a temperature of several million degrees Celsius. This hot spot produced a strong magnetic field, which was measured by a series of magnetic probes placed around the target.

The experiments showed that the magnetic field strength increased with the rotation speed of the plasma. This is consistent with the dynamo mechanism, which predicts that the magnetic field strength should be proportional to the rotation rate. The experiments also showed that the magnetic field was generated by the flow of electric currents in the plasma.

The results of the experiments provide strong evidence for the dynamo mechanism as the origin of the magnetic field in magnetars. This mechanism is also thought to be responsible for the generation of magnetic fields in other types of neutron stars and pulsars.