A Coronal Hole Targets Earth High speed solar wind particles from a large coronal hole are buffeting Earth's magnetosphere. The end of February could mark another good weekend for aurora watchers, thanks to a large coronal hole currently straddling the visible disk of the sun. High speed solar wind particles streaming out of the hole reached the Earth today and began to buffet our planet's magnetosphere. Space weather forecasters expect moderate to high levels of aurora borealis with minor impacts on satellite operations and high latitude power grids for the next few days. The resulting gusts of solar wind is expected to strike Earth's magnetic field and trigger moderate geomagnetic disturbances over the next few days.
Coronal holes are easy to spot by looking at the Sun through an x-ray telescope.
They appear as very dark areas that contrast with bright spots overlying sunspot groups. Hot gas around sunspots is captured by magnetic fields that rise up out of one sunspot and bend back to reconnect at another spot nearby. These glowing 'magnetic bottles' shine brightly at x-ray wavelengths. The magnetic fields around coronal holes are different. Instead of looping back to reconnect on the sun's surface, these magnetic fields are essentially open.