Earth’s inner core and the geomagnetic field. Credit: IGCAS
A geomagnetic field is created in the Earth’s interior and extends into outer space to protect the Earth from cosmic radiation and charged particles of the solar wind. The magnetic field is generated by convection of charged molten iron fluids in the Earth’s outer core.
In contrast to the homogeneous convective outer core, the Earth’s inner core is heterogeneous and anisotropic. The seismic velocity in the polar direction is about 2–3% faster than the velocity in the equatorial direction.
Recently, it is led by professor researchers. Li Heping and He Yu of the Institute of Geochemistry of the Chinese Academy of Sciences (IGCAS) revealed that the Earth’s interior core structure is driven by the dipole geomagnetic field.
The study has been published in Nature Communications On March 24th.
Last year, a study was published in nature He revealed that the Earth’s inner core is not naturally solid but a composition of solid iron and liquid-like light elements (hydrogen, oxygen and carbon), which is also known as the ionic superstate.
In the current study, the researchers found that the hexagonal Fe-H-coated alloy (hcp) showed both seismic anisotropy and H-ion diffusion anisotropy under conditions of high pressures and temperatures in the Earth’s inner core.
In the presence of an external electric field, the alignment of the Fe–H lattice with the c-axis pointing in the direction of the field was energetically favourable. Due to this effect, the alignment of the Fe–H lattice can be driven by an electric field.
Given the distribution of the electromagnetic field in the inner core, an interaction was established between the inner core and the geomagnetic field. The aligned texture driven by the geomagnetic field showed large seismic anisotropy, which explains the anisotropic seismic velocities in the inner core.
“It’s intriguing! Hydrogen mobile within the Earth’s inner core may be associated with the geomagnetic field and thus form an anisotropic tapestry, which should give us a new perspective to understand the mysteries of the Earth’s inner core and the Earth’s magnetic field,” said Dr. He. Yu, corresponding study author.
“In addition to the implications for Earth sciences, the unique physical properties of the superfluid impact are also vital for us to understand the behaviors of superionic matter under the extreme conditions of the interiors of exoplanets,” said Dr. Sun Xichuan, first author of the study.
more information:
Shichuan Sun et al, Superionic Effect and Anisotropic Texture in Earth’s Inner Core Driven by the Geomagnetic Field, Nature Communications (2023). DOI: 10.1038/s41467-023-37376-1
the quote: Earth’s Anisotropic Interior Core Structure Driven by Dipolar Geomagnetic Field, Study Reveals (2023, March 31) Retrieved March 31, 2023 from https://phys.org/news/2023-03-earth-anisotropic-core- driven-dipole. html
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