The Irish Magnetometer Network (MagIE) is a network of geomagnetic observatories in Ireland. MagIE is a project which was set up by the Dublin Institute of Advanced Studies(DIAS) and Trinity College Dublin in 2012, with the aim of building magnetometer observatories across Ireland to monitor geomagnetic storms and their effects. MagIE currently consists of three permanent magnetometer observatories, two of which were set up in Birr and Armagh, to complement the existing Met Éireann Valentia observatory.
Each site calculates geomagnetic and geoelectric(where possible) field strengths via the third generation Long-Period Magnetotelluric Instrument (LEMI-417M). Each instrument is composed of a fluxgate magnetometer, a set of electrodes, a recording unit and a GPS unit for time-stamping.
Using the readings from the LEMI-417M instruments, the K-indices can be calculated to measure local disturbances in Earth’s magnetic field strength. Large K-values indicate that the northern lights (aurora borealis) have a high probability of being visible from Ireland. The K-indices are calculated using the FMI method.
Why Research Geomagnetic Storms?
A geomagnetic storm is a large disturbance of Earth’s magnetic field due to the interaction of the magnetic field with the solar wind. The increased densities in the solar wind allows charge particles to precipitate into the region of the Earth’s upper atmosphere known as the Ionosphere. These charges generate currents, which in turn, generate varying magnetic fields and cause geomagnetic storms. During Coronal Mass Ejections(CMEs), these large disturbances are generated. Geomagnetic storms can also form when a coronal hole faces the Earth, although these are generally less significant. During geomagnetic storms geomagnetically-induced-currents(GICs) are generated. GICs are induced currents which form in conductors on the surface of the Earth (i.e. wires) due to the considerably large electric fields felt at the surface of the Earth caused by the varying magnetic fields in the Ionosphere. GICs pose risks to ground infrastructure such as power-grids and telecommunications. For power-grids, GICs add a quasi-DC current to the grid, which leads to heating in transformers, which in turn, can damage transformers beyond use in extreme conditions. GICs can also damage telephone/telegraph networks, undersea cables and increase erosion of pipelines and railways in a similar manner to power-grids.
Another effect during geomagnetic storms is an increased disturbance in GPS signals. GPS signals pass through the Earth’s upper atmosphere. In the Ionosphere, currents are generated due to the precipitation of charged particles from the solar wind. These charges causes signals to be delayed/deflected. For large geomagnetic storms, the precipitation of charges can increase dramatically, which can lead to errors in GPS coordinates of up to tens of metres.
