Tachocline mystery: NASA supercomputer unlocks Sun’s magnetic heart

The article discusses a breakthrough in understanding the Sun’s tachocline, a thin transition layer between its inner radiative zone and outer convective zone, which is crucial for the Sun’s magnetic activity. Despite its small size, the tachocline plays a key role in generating solar phenomena such as flares and coronal mass ejections. For decades, scientists struggled to explain why this boundary remains so thin and stable. Researchers at the University of California, Santa Cruz, using NASA’s Pleiades supercomputer, conducted extensive simulations that finally captured the tachocline’s behavior realistically. Their models revealed that, contrary to previous beliefs emphasizing fluid viscosity, radiative spreading is the dominant process affecting the tachocline’s thickness. Importantly, the simulations showed a feedback loop where the Sun’s magnetic fields, generated by the dynamo process in the convective zone, help maintain the tachocline’s narrowness. This discovery not only resolves a longstanding solar physics puzzle but also has practical implications. Understanding