New research may improve solar storm predictions

BOULDER, Colo., April 7 (UPI) -- A new study promises an improved understanding of the sun's seasonal changes -- changes that dictate the sun's electromagnetic behavior.

In the new report, scientists at the National Center for Atmospheric Research detail the manner in which bands of strong magnetic fields in each solar hemisphere influence seasonal solar activity -- the waxing and waning of solar storms' frequency and power.

By better measuring the ways these solar bands govern the sun's 11-year solar cycles (and its broader 22-year cycle), scientist hope to improve solar storm forecasting. Better predicting powerful solar flares and coronal mass ejections could help engineers protect satellite communication systems and electrical grids from disruption.

According to the research team, these overlapping pairs of parallel bands represent high-density concentrations of magnetic fuel. Fueled by the rotation of the sun's deep interior, the bands travel from the poles in each hemisphere toward the equator over a 22-year period, finally meeting and dissipating. Along the way, their behavior is linked with peaks and lulls in electromagnetic activity on the sun's surface.

"What we're looking at here is a massive driver of solar storms," lead study author Scott McIntosh, director of NCAR's High Altitude Observatory, said in a press release. "By better understanding how these activity bands form in the Sun and cause seasonal instabilities, there's the potential to greatly improve forecasts of space weather events."

The bands are similar to the currents and air and ocean that dictate Earth's climate and weather patterns. Just as upwelling of cold water can push concentrations of warm water to the ocean surface and influence large storm systems, surges of electromagnetic fuel from the sun's interior can rise up through the tachocline (an intermediary region of the sun's shallow interior) and disrupt the star's corona.

"Much like Earth's jet stream, whose warps and waves have had severe impact on our regional weather patterns in the past couple of winters, the bands on the Sun have very slow-moving waves that can expand and warp it too," explained co-author Robert Leamon, a scientist at Montana State University. "Sometimes this results in magnetic fields leaking from one band to the other. In other cases, the warp drags magnetic fields from deep in the solar interior, near the tachocline, and pushes them toward the surface."

By combining this new understanding of seasonal solar variations with current forecasting models, which monitor sun spots and other activity, researchers say predicting solar storms will become a much more precise science.

"If you understand what the patterns of solar activity are telling you, you'll know whether we're in the stormy phase or the quiet phase in each hemisphere," McIntosh said. "If we can combine these pieces of information, forecast skill goes through the roof."

The new research was published this week in the journal Nature Communications.