The mystery of inner core dynamics: mechanisms of Inner core rotation
The Earth’s inner core is located at the centermost part of the earth. It has a relatively small volume compared to other parts of the earth, therefore it records geodynamic processes for the outer core and the mantle. Superrotation (also called inner core rotation ) is one of the important geodynamic activities going on within the inner core that is caused by the core-mantle coupling. Electromagnetic coupling, gravitational coupling, and mechanical coupling are three major mechanisms of inner core rotation that are widely accepted by most researchers. Studies of electromagnetic coupling explained how electromagnetic torques act on the inner core. Gravitational coupling study approaches from the impaction of gravitational anomalies within the mantle on the inner core. A more comprehensive study discussed several possible combinations of electromagnetic torque, gravitational torques, and mechanical torque affecting the inner core dynamics. However, it is hard to find a consistent number of the angular velocity of rotation and the exact amount of torques acting on the inner core from previous studies. Besides, new discoveries of the nature of the inner core make it even harder to explain the inner core dynamics.
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