Scientists Trace Solar Storm Origins to Hidden Layer Deep Inside the Sun

The solar storms bring explosive releases of radiation and charged particles, which occur when solar activity reaches peak sunspot levels. The researchers need to find the source of the magnetic forces which create solar storms. Physicists at the New Jersey Institute of Technology have now identified the origin in a study published in Scientific Reports: a thin layer known as the tachocline, located about 200,000 kilometers or 16 widths of the Earth below the surface of the Sun.

Deep Shearing Motions Drive the Solar Cycle

According to the paper, the tachocline is a razor-thin transition zone between the turbulent outer convection zone and the stable radiative zone. The sudden changes in rotation trigger powerful shearing motions in the charged plasma. These are just right for boosting magnetic fields. Mandal and Kosovichev studied almost three decades' worth of acoustic data from NASA's SOHO satellite and the GONG network of telescopes on the ground. These can sense tiny ripples on the sun's surface caused by flows in the deep interior. The researchers found rotating bands of plasma in the tachocline take on a butterfly shape, echoing sunspot migration to the equator in each 11-year cycle.

Space Weather Forecasts

Solar flares and coronal mass ejections create operational problems for satellites and communications systems, and power grids which operate on Earth. Right now, many of the forecasting models only include near-surface solar processes. But the new research indicates that the whole convection zone, particularly the tachocline region, has to be taken into account. The sun's interior layer undergoes changes which require multiple years before they become visible on the surface. This development will enable scientists to detect upcoming dangerous solar events through precise early warning systems, which will provide them with early and accurate signals.