magnetic storm
A worldwide disturbance in the Earth's magnetic field. These storms result from variations in the solar wind that produce major changes in the currents, plasmas, and fields in Earth's magnetosphere. They can last from several hours to many days. The largest storms often result from coronal mass ejections (CMEs), while coronal hole high-speed streams (CH HSS) and co-rotating interaction regions (CIRs) can also lead to periods of storming. Geomagnetic activity is normally measured by surface-based magnetometers and quantified by several indexes to include the commonly used Kp index and storm levels classified with use of the National Oceanic and Atmospheric Administration G-scale.
GFZ German Research Centre for Geosciences, 2018: Frequently asked questions regarding geomagnetism: What is a geomagnetic storm? Accessed 14 August 2018. Available at https://www.gfz-potsdam.de/en/section/geomagnetism/data-products-services/frequently-asked-questions-faqs/#c14390.
Space Weather Prediction Center, 2018: Geomagnetic storms. Accessed 14 August 2018. Available at https://www.swpc.noaa.gov/phenomena/geomagnetic-storms.
Term edited 14 August 2018.
