A review of progress in modelling of induced geoelectric and geomagnetic fields with special regard to induced currents

Abstract

Summary. The Earth's lithosphere and mantle responds to Space Weather through time-varying, depthdependent induced magnetic and electric fields. Understanding the properties of these electromagnetic fields is a key consideration in modelling the hazard to technological systems from Space Weather. In this paper we review current understanding of these fields, in terms of regional and global scale geology and geophysics. We highlight progress towards integrated European-scale models of geomagnetic and geoelectric fields, specifically for the purposes of modelling geomagnetically induced currents in power grids and pipelines.

Towards quantitative assessment of the hazard from space weather. Global 3-D modellings of the electric field induced by a realistic geomagnetic storm

“…So far, most studies of the geoelectric field in connection with GIC were performed on a regional or local scale, considering rather simplified models of the inducing geomagnetic source (see review paper of Thomson et al (2009) for more details). In addition, most of the studies (except for the works by Beamish et al, 2002;Thomson et al, 2005 andGilbert, 2005) employed the assumption of a one-dimensional (1-D) conductivity structure of Earth.…”

Space Weather Quarterly Volume 14, Issue 2, 2017

“…Geoelectric time series are useful for validating models and prediction methods, as well as for extending the depth of magnetotelluric investigations of the mantle's electrical conductivity structure [e.g., Schultz et al, 1987;Toffelmier and Tyburczy, 2007]. But due to the complexity of the Earth's interior structure, storm time geoelectric fields measured at one site can differ significantly from those measured at another just a hundred or so kilometers away [e.g., Bedrosian and Bonner and Schultz, 2017].…”

“…For the United States, completing the national magnetotelluric survey and improving real-time geomagnetic monitoring are high priorities [e.g., Thomson et al, 2009;Love et al, 2014]. Looking beyond statistical hazard maps, ongoing algorithm development [e.g., Bonner and Schultz, 2017;Kelbert et al, 2016;Weigel, 2017] could enable time-series scenario mapping of individual magnetic storms-convolving a timedependent map of ground-level geomagnetic disturbance, derived from ground-based magnetometer data [e.g., Pulkkinen et al, 2003;Rigler et al, 2014], with a map of Earth-surface impedance.…”

“…Of particular concern is the storm time induction of geoelectric fields in the Earth's electrically conducting interior [e.g., Thomson, 2007]. During intense magnetic storms, these geoelectric fields can interfere with the operation of electric-power grids, sometimes even damaging high-voltage transformers and causing blackouts [e.g., Piccinelli and Krausmann, 2014].…”

Magnetic Storms and Induction Hazards

“…In principle, empirically parameterized maps of the temporal evolution of ground-level magnetic disturbance can be constructed by fi tting basis function model parameters to ground magnetometer data [e.g., Pulkkinen et al , 2003 ], thus fi lling in the geography between magnetometer stations. Timeconvolutional fi ltering of a magnetic activity map through a conductivity model can give a geoelectric fi eld map [e.g., Thomson et al , 2009 ]. Geoelectric model accuracy can be established by comparison with geoelectric measurements, and indeed, a geoelectric modeling project can inform evaluations of the adequacy of the existing ground magnetometer network.…”