Members of the Geomagnetism, Paleomagnetism and Electromagnetism Section study the magnetic field, from Earth’s core to other planets and to outer space, to gain an understanding of Earth’s structure, dynamics, and history and its relationship to other planets. Geomagnetists measure the Earth’s magnetic field at present and use measurements taken over the past few centuries to devise theoretical models to explain its origin. Paleomagnetists have an eye to history: they interpret fossil magnetization in rocks and sediments from the Earth’s continents and oceans, which record the spreading of the seafloor, the wandering of the continents, and the many reversals of polarity that Earth’s magnetic field has undergone through time; similar data can be analyzed from extraterrestrial bodies. Electromagnetists employ changing magnetic fields for fundamental research purposes and for the benefit of mankind, by measuring the small electrical currents that can be induced in the crust and mantle and interpreting them in terms of electrical conductivity.
Other key aspects of GPE research are the physics and chemistry of magnetic minerals, which deal with how they are formed and become magnetized and shed light on ancient climate and environment; magnetic anomalies, which offer clues about the subsurface vital for understanding the crust; and electromagnetic induction, which delineates structures deep within the planet related to variations in composition, temperature, and other properties. Keeping track of changes in the magnetic field and providing free data to researchers through a global network of permanent geomagnetic observatories are also important to the section. Exciting developments at the forefront of GPE research include breakthroughs in supercomputer geodynamo simulation that are, for the first time, producing Earth-like magnetic fields and giving new insights into the dynamics of the core; aeromagnetic surveys in Antarctica that are helping to determine the geology, lithospheric structure, and tectonic evolution below the ice; understanding the fundamentals of rock magnetism using new imaging devices that can discern structures on the nannoscale; and instrumental developments that allow reliable collection of electrical data on both land and at the bottom of the ocean.