Geomagnetic Storms : Hits Earth
The strongest geomagnetic storm in over two decades recently hit Earth, causing radio blackouts and extending the northern lights to the southern United States.
- Geomagnetic Storm is a major disturbance of Earth’s magnetosphere that occurs when there is a very efficient exchange of energy from the solar wind into the space environment surrounding Earth.
- These storms result from variations in the solar wind that produce major changes in the currents, plasmas, and fields in Earth’s magnetosphere.
- The solar wind conditions that are effective for creating geomagnetic storms are sustained (for several hours) periods of the high-speed solar wind and a southward-directed solar wind magnetic field (opposite the direction of Earth’s field) at the dayside of the magnetosphere.
- The largest such storms are associated with solar coronal mass ejections (CMEs), where a billion tons or so of plasma from the sun, with its embedded magnetic field, arrives at Earth.
- It results in intense currents in the magnetosphere, changes in the radiation belts, and changes in the ionosphere, including heating the ionosphere and an upper atmosphere region called the thermosphere.
- These storms can heat the ionosphere, causing beautiful auroras on earth.
- Because the ionosphere is heated and distorted during storms, long-range radio communication that relies on sub-ionospheric reflection gets affected.
- Ionospheric expansion due to these storms can increase satellite drag and make their orbits difficult to control.
- Satellite electronics can be damaged through the buildup and discharge of static-electric charges.
- It can disrupt global navigation systems.
- It can create harmful geomagnetic-induced currents (GICs) in the power grid and pipelines.
