Geomagnetic disturbances (GMDs) are natural occurring events that are known to negatively affect the normal operation of modern technology. One of the major causes for these disturbances is the sun. In addition to supplying visible light that is essential for most of the life on Earth, the sun emits other forms of energy. These other forms of energy include sudden bursts of electromagnetic radiation associated with solar flares and high concentrations of ionized particles (plasma) known as coronal mass ejections (CMEs).
As a CME nears, the charged particles begin to interact with the Earth in a number of ways including causing observable changes in the magnetosphere and a build up of circulating currents in the ionoshphere. This build up is the source of the southern- (aurora australis) and northern-lights (aurora borealis), which offer the only visible representation of a CME event.
With the changes in the Earth’s magnetic field and the added build up of charged particles in the ionosphere, currents can be naturally added to long conductors like transmission lines of the electrical power grid. These naturally occurring geomagnetically induced currents (GICs) can have a devastating impact to normal system operation and can lead to full system collapse.
Real World Cases
- 03/13/1989 Hydro-Quebec
- 08/28/1859 Carrington Event
- Ancient Supernova Explosion
Planetary K Index
The K-index quantifies disturbances in the horizontal component of earth's magnetic field with an integer in the range 0-9 with 1 being calm and 5 or more indicating a geomagnetic storm. It is derived from the maximum fluctuations of horizontal components observed on a magnetometer during a three-hour interval.