What is the Magnetosphere?
The magnetosphere is the region around Earth where the planet's magnetic field dominates over the solar wind. It acts as a shield, deflecting most of the charged particles from the Sun. On the dayside it is compressed by the solar wind; on the nightside it stretches into a long magnetotail. The boundary between the magnetosphere and the solar wind is the magnetopause.
Interaction with Solar Wind and CMEs
When the solar wind is strong or when a CME arrives, the magnetosphere is compressed and disturbed. Magnetic reconnection can allow solar wind particles to enter along field lines toward the poles, where they hit the upper atmosphere and produce aurora. This disturbance is measured as geomagnetic activity (e.g. Kp index). Cosmic Radar shows the daily Kp so you can see when the magnetosphere is being stressed.
Sources and further reading
- NASA – Magnetosphere – Earth's magnetic field and solar wind
- NOAA – Geomagnetic storms – Storm effects and Kp
- ESA Space Weather – European monitoring