Geomagnetic storm

Magnetosphere rendition

Aurora borealis2, Churchill, MB

ExtremeEvent 19890310-00h 19890315-24h

magnetopause

Geomagnetic storm is a temporary disturbance of the Earth's magnetosphere caused by a solar wind shock wave and/or cloud of magnetic field that interacts with the Earth's magnetic field. The increase in the solar wind pressure initially compresses the magnetosphere. The solar wind's magnetic field interacts with the Earth's magnetic field and transfers an increased energy into the magnetosphere. Both interactions cause an increase in movement of plasma through the magnetosphere (driven by increased electric currents in the magnetosphere) and an increase in electric current in the magnetosphere and ionosphere.

Causes

Geomagnetic storms are caused by the Sun's activity, such as solar flares, coronal mass ejections (CMEs), and high-speed solar wind streams emanating from solar coronal holes. The intensity of geomagnetic storms is measured on the G-scale, which ranges from G1 (minor) to G5 (extreme).

Effects

Geomagnetic storms can have a variety of effects on Earth, ranging from minor disturbances to significant disruptions. These effects include disturbances in radio propagation, causing problems with communication systems, navigation systems (like GPS), and power grid failures. They can also increase the drag on satellites in low-Earth orbit, and they are known to cause beautiful aurora displays at high latitudes.

Technological Impact

The most significant impact of geomagnetic storms is on human-made systems. Power grids can be affected as geomagnetically induced currents (GICs) can overload systems, leading to widespread power outages. Communication and navigation systems can also be disrupted, affecting everything from cell phone reception to GPS accuracy.

Biological Impact

There is ongoing research into the effects of geomagnetic storms on biological systems, including potential impacts on human health. However, conclusive evidence linking geomagnetic activity to biological effects is still lacking.

Prediction and Monitoring

The prediction of geomagnetic storms is a focus of ongoing research. The Space Weather Prediction Center (SWPC), part of the National Oceanic and Atmospheric Administration (NOAA), is one of the primary organizations that monitor space weather and provide alerts and forecasts. Predictions are based on observations of the Sun and solar wind data collected by satellites such as SOHO (Solar and Heliospheric Observatory) and ACE (Advanced Composition Explorer).

Historical Events

Some notable geomagnetic storms include the Carrington Event of 1859, which is the largest geomagnetic storm on record. It caused widespread telegraph system failures. Another significant event occurred in March 1989, leading to a blackout in Quebec, Canada.

See Also

• Solar flare
• Coronal mass ejection
• Aurora
• Magnetosphere
• Solar wind