A temporary disturbance of Earth's magnetosphere caused by solar wind and magnetic field interactions.A temporary disturbance of Earth's magnetosphere caused by solar wind and magnetic field interactions. When the solar wind carries a strong southward magnetic field, it can reconnect with Earth's northward magnetic field lines, allowing energy and particles to enter the magnetosphere. This leads to enhanced electric currents, auroras, and can disrupt satellites, power grids, and communications.
The connection between solar activity and magnetic disturbances on Earth was first recognized in the 19th century, with the Carrington Event of 1859 being a famous early example. The term 'magnetic storm' was coined by Alexander von Humboldt.
The solar wind compresses Earth's magnetic field on the day side and stretches it into a long tail on the night side. During a magnetic storm, magnetic reconnection occurs, injecting high-energy particles into the inner magnetosphere. These particles create intense ring currents that alter the magnetic field at Earth's surface, which is measured by magnetometers.
Magnetic storm forecasting is crucial for protecting power grids, GPS systems, and satellites from damage caused by induced currents and radiation.
The largest recorded magnetic storm, the Carrington Event of 1859, caused auroras visible as far south as the Caribbean and disrupted telegraph systems worldwide.













