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Bioelectromagnetism

Te geodynamo simulations suggested that active heat transport from the outer core to the mantle

may result in more active convection in the outer core, resulting in instability in the geodynamo. Hence,

it is speculated that the activation of mantle convection could cause GMF reversals together with the

activation of volcanic activity.

Additional reports now understand that the solid inner core is growing in the Earth’s core, which is

the source of convective energy in the liquid outer core (Lister and Bufett, 1995; Jones, 2015; Lythgoe

et al., 2015). Te Earth has been a heat engine that has been cooling since its birth, but the inner core is

growing as it cools. When the solid inner core grows, the light elements contained in the liquid outer

core are released, and convection occurs when they rise toward the mantle (Zhang et al., 2016). Te

compositional convection (the driving force is the density diference due to the diference in composi­

tion) and the thermal convection (the driving force is the density diference due to heat) are considered

to be main geodynamo energy sources (Lister and Bufett, 1995; Lythgoe et al., 2015). Moreover, latent

heat released when the inner core solidifes can also cause thermal convection. Just changing the ther­

mal conditions at the CMB can alone account for the full spectrum of temporal variations in the GMF

reversal rate (Driscol and Olson, 2011; Olson et al., 2013). However, it is speculated that the driven efect

of the compositional convection on the geodynamo might be larger than that of the thermal convection

(Lythgoe et al., 2015).

According to a recent study published in the journal Nature Geoscience, the inner core is growing

lopsidedly (Frost et al., 2021). One half of the sphere, the eastern half under Indonesia’s Banda Sea,

accrues 60% more iron crystals than its western counterpart, which is located under Brazil (Frost et al.,

2021). Frost’s team (Daniel Frost, a leading seismologist at the University of California, Berkeley) created

geomagnetic growth models and conducted mineral physics calculations that tracked the inner core’s

growth over the last billion years (Frost et al., 2021). According to Science News (Woodward, 2021),

briefy, they found that its lopsided nature likely began as soon the core formed.

“Every layer in the Earth is controlled by what’s above it, and infuences what’s below it,” Frost told

Live Science from Specktor (2021). If iron is crystallizing more quickly on one side of the inner core than

the other, it means that the outer core is cooling faster on that side (Woodward, 2021). So the mantle on

that side, in turn, must be cooling the outer core faster than the mantle on the other side (Woodward,

2021). Te genesis of that cooling chain, Frost said, could be Earth’s tectonic plates (Woodward, 2021).

When one plate pushes up against another, one subducts, or sinks, below the other (Woodward, 2021).

Te subducting plate cools the mantle in that area of the planet (Woodward, 2021). Earth’s core plays

a key role in protecting the planet from dangerous solar wind and GCRs (Woodward, 2021). Swirling

iron in the outer core generates an MF that stretches all the way from there to the space surrounding

our planet (Woodward, 2021). Tat swirl happens, in part, because of a process in which hotter, lighter

material from the outer core rises into the mantle above (Woodward, 2021). Tere, it swaps places with

cooler, denser mantle material, which sinks into the core below (Woodward, 2021). Tis convection also

happens between the inner and outer core, so if various parts of the outer and inner core are cooling at

diferent rates, that could afect how much heat gets exchanged at the boundary, which might have an

impact on the swirling engine powering Earth’s protective sheath (Woodward, 2021). “Te question is,

does this change the strength of the MF?” Frost told Live Science (Specktor, 2021). Questions this big are

beyond the scope of the team’s new paper, but Frost said he has begun work on new research with a team

of geomagnetists to investigate some possibilities (Specktor, 2021).

Other geodynamo energy sources are precession and tidal interactions (Olson, 2016). Tides distort

the CMB, and precession derives their energy from the Earth’s rotation. Precession is caused by the

torques on the Earth’s equatorial bulge and the Earth’s axis of rotation precesses once every 26 kyr. In

another aspect, the GMF reversal frequency would have been very sensitive to variations in the vigor of

the convection in the Earth’s liquid outer core. Yadav et al. (2016) expected that fow in the outer core

might be primarily governed by (1) the Coriolis force due to the Earth’s rotation, (2) the buoyancy force

driving the convection, and (3) the Lorentz force due to the GMF. Tat is, these expectations suggested

that the outer core fow might be governed by a balance between Lorentz force, rotational force, and