Scientists at the University of Cambridge have found a possible explanation for the anomalous shift of the Earth's magnetic field to the west. According to the researchers, the drift is due to the Rossby waves, which form in the planet's outer core. This was announced in a press release on Phys.org.
The displacement was discovered back in 1962, while the exact cause of the magnetic field variation remains unknown. According to one hypothesis, eddy currents are created in the outer core of the Earth, which is a liquid layer 2266 kilometers thick, reminiscent of high-altitude jet currents in the Earth's atmosphere - narrow and meandering air currents at an altitude of 9-12 kilometers, caused by the Coriolis force. However, no signs of such flows were found.
According to the researchers, the drift can be caused by Rossby waves, which are formed in rotating liquids and gases. They are slow traveling waves that form in the oceans and atmosphere of the Earth, as well as in the gas envelopes of other planets and the outer layers of stars. In the atmosphere, they are represented by bends of high-altitude winds, and ocean waves run at the border of a warm and cold water layer.
Rossby waves also form in the outer core and are believed to be responsible for the displacement of the magnetic field, despite the fact that they are traveling eastward. By analogy with ocean waves, which can move objects in the opposite direction to their motion, disturbances in the core can "push" the magnetic field to the west. However, this hypothesis needs to be tested.