Solar storm's magnetic cloud expanded 21% and tripled in heat

Researchers at the University of Iowa documented unusual behavior in a magnetic cloud from a coronal mass ejection on November 4–5, 2021: it expanded 21% and heated threefold on its way to Earth. Solar Orbiter and Wind spacecraft, nearly aligned along the Sun-Earth line, captured the measurements.

• The cloud expanded at 192 km/s versus the typical 50–100 km/s
• Plasma tripled in temperature over just 13 million miles
• Magnetic field pressure stayed unchanged, defying existing models
• The eruption triggered a major geomagnetic storm on Earth