Solar wind live

What is the solar wind?

The solar wind is a continuous stream of charged particles, mostly protons and electrons, escaping the Sun's corona at 300 to 800 km/s and carrying the interplanetary magnetic field with it. Spacecraft at the L1 Lagrange point, 1.5 million kilometres sunward of the Earth, measure it about an hour before it reaches the magnetosphere.

Three quantities matter for space weather. The speed, calm around 400 km/s, fast above 600 km/s during coronal holes and coronal mass ejections. The proton density, which jumps when a shock front passes. And above all the Bz component of the field: when it turns strongly negative, pointing south, the interplanetary field connects to the Earth's and energy pours in, triggering storms and auroras.

The 24 h and 7-day views show the one-minute NOAA SWPC data; beyond that, the page switches to NASA's hourly OMNI archive, which goes back to 1963.