The sun's magnetic field, which causes solar storms like the one that hit Earth this month and produced beautiful auroras, may originate at shallower depths in the star's interior than previously thought, according to researchers. The sun's outer 30% comprises an "ocean" of churning gases plunging more than 130,000 miles (210,000 kilometers) below the solar surface. The research, comparing new theoretical models to observations by the sun-observing Solar and Heliospheric Observatory (SOHO) spacecraft, provides strong evidence that its magnetic field is generated near the top of this ocean – less than 5% inward, or about 20,000 miles – rather than near the bottom, as long hypothesized.
In addition to providing insight into the sun's dynamic processes, the findings may improve the ability to forecast solar storms and guard against potential damage to electricity grids, radio communications and orbiting satellites, the researchers said. Most stars have magnetic fields, apparently generated by the motion of super-hot gases inside them. The sun's ever-changing magnetic field drives the formation of sunspots – shifting dark patches – on its surface and triggers solar flares that blast hot charged particles into space.
"The top 5% to 10% of the sun is a region where the winds are perfect for making abundant magnetic fields through a fascinating astrophysical process," said Geoffrey Vasil, an applied and computational mathematician at the University of Edinburgh in Scotland a.