Flare: Radiation
A solar flare is a burst of electromagnetic radiation (X-rays, UV, visible light) from the Sun's atmosphere. It travels at the speed of light and reaches Earth in ~8 minutes. It can cause ionospheric disturbances and radio blackouts but does not carry significant mass or magnetic field to Earth.
CME: Mass and Field
A coronal mass ejection (CME) is an eruption of plasma and magnetic field from the corona. It travels at hundreds to over 2000 km/s and typically reaches Earth in 1–3 days. When it hits the magnetosphere, it can trigger geomagnetic storms and aurora. Not every flare has a CME; not every CME is associated with a strong flare. Cosmic Radar shows both in the daily report.
Sources and further reading
- NOAA – Solar flares – Flares and radiation
- NOAA – CMEs – CMEs and arrival times
- SOHO LASCO – CME imagery