A supernova explosion blasts off the outer layers of a dying star. What remains is the core — a neutron star, packed into a sphere the size of a city. The existence of such stars was predicted back in 1934 by Fritz Zwicky. But the culinary drama doesn’t end there: part of the ejected matter falls back in an Accretion disk, forming a scorching liquid layer — a kind of liquid dough on the star’s surface.
In this layer, heated to two billion degrees, turbulent eddies rage. They act like a baker’s hands, energetically kneading the dough. The motions of the plasma pick up and twist magnetic field lines, amplifying them manifold. This process is called a magnetic dynamo.
To test the idea, astrophysicists performed a numerical simulation. In a cubic volume with a side of 100 meters, they recreated the conditions of the liquid layer: density 10¹⁰ g/cm³, temperature 2×10⁹ K, initial field 10¹² G. They included neutrino cooling and a realistic equation of state.
The results were stunning. In just one millisecond, the field saturated, reaching 3–7×10¹³ G. The magnetic energy accounted for 20–30% of the turbulent kinetic energy — as if every fifth calorie spent on kneading went into making the dough rise. The field structure resembled a tangled ball of threads and sheets, while the matter density remained nearly unchanged.
This discovery solves a long-standing puzzle. pulsars and some magnetars show a weak external magnetic field, yet their activity requires a powerful hidden reservoir. Turbulent dynamo creates just such a field — strong but small-scale, tucked away deep inside the star. Someday, over thousands of years, diffusion in the solid crust will reprocess it into the observable dipole. By the way, pulsars themselves — rapidly rotating neutron stars — were first discovered in 1967 by Jocelyn Bell Burnell.
Thus, in the depths of a newborn star, a culinary wonder unfolds. The turbulent kneading turns weak magnetic seeds into a dramatic surge of the field. And all this in a millisecond. It is this process that may kick-start the convoluted evolution of magnetars, whose flares light up galaxies.
In the time it takes you to blink (about 100 milliseconds), the magnetic field in the liquid layer of a newborn neutron star would have amplified a hundredfold and reached saturation. Meanwhile, neutrino cooling — the main cooling mechanism — would not have removed even a millionth of the thermal energy in those same instants: the cooling lasts for weeks.
In Robert Forward's novel "Dragon's Egg", a neutron star serves as the cradle of hyper-dense life, whose civilization develops on the surface at a breakneck pace. If such creatures existed, turbulent eddies on millisecond timescales would be geological epochs for them, and magnetic field surges would be natural cataclysms, giving rise to 'magnetic mountains' and aurorae of unimaginable scale.