Ohmic and viscous damping of inner core translational oscillations

Fuente: arXiv
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Hauptverfasser: Personnettaz, Paolo, Cébron, David, Schaeffer, Nathanaël, Deguen, Renaud, Mandea, Mioara
Format: Preprint
Veröffentlicht: 2026
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author Personnettaz, Paolo
Cébron, David
Schaeffer, Nathanaël
Deguen, Renaud
Mandea, Mioara
author_facet Personnettaz, Paolo
Cébron, David
Schaeffer, Nathanaël
Deguen, Renaud
Mandea, Mioara
contents Large earthquakes can trigger translational oscillations of Earth's inner core (Slichter modes), yet their damping remains uncertain. Using simulations, we quantify viscous and Ohmic dissipation in the fluid outer core. Earth's rotation splits the motion into one polar and two equatorial modes. We explore all three and derive scaling laws for the quality factor with each dissipation mechanism. Viscous effects are negligible, confined to a thin layer at the inner core boundary. Ohmic dissipation dominates, with decay times of 3-16 years. Equatorial modes damp at least twice as fast as the polar mode. Our results suggest that Slichter modes can persist for years. Their continued non-detection is therefore more likely due to weak excitation than rapid damping.
format Preprint
id arxiv_https___arxiv_org_abs_2604_21417
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Ohmic and viscous damping of inner core translational oscillations
Personnettaz, Paolo
Cébron, David
Schaeffer, Nathanaël
Deguen, Renaud
Mandea, Mioara
Geophysics
Large earthquakes can trigger translational oscillations of Earth's inner core (Slichter modes), yet their damping remains uncertain. Using simulations, we quantify viscous and Ohmic dissipation in the fluid outer core. Earth's rotation splits the motion into one polar and two equatorial modes. We explore all three and derive scaling laws for the quality factor with each dissipation mechanism. Viscous effects are negligible, confined to a thin layer at the inner core boundary. Ohmic dissipation dominates, with decay times of 3-16 years. Equatorial modes damp at least twice as fast as the polar mode. Our results suggest that Slichter modes can persist for years. Their continued non-detection is therefore more likely due to weak excitation than rapid damping.
title Ohmic and viscous damping of inner core translational oscillations
topic Geophysics
url https://arxiv.org/abs/2604.21417