Open AccessThe Magnetic Field Induced by the Bodily Tide in the Core of the Earth
Author(s) -
C. L. Pekeris
Publication year - 1971
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.68.6.1111
Subject(s) - dynamo theory , dynamo , core (optical fiber) , magnetic field , physics , coupling (piping) , geophysics , field (mathematics) , earth (classical element) , term (time) , coupling coefficient of resonators , geodesy , quantum electrodynamics , condensed matter physics , nuclear magnetic resonance , geology , mathematics , materials science , optics , mathematical physics , quantum mechanics , resonator , pure mathematics , metallurgy
The motion in the liquid core of the earth due to the bodily tide can induce a periodic magnetic field having the frequency σ of the tide as well as multiple frequencies, including a steady term. The coupling coefficient for the steady term between the convectively inducing and induced fields is estimated to be of the order of σH 2 /λ, whereH denotes the height of the equilibrium tide, and λ = 1/4πκ, κ denoting the electrical conductivity of the core. With σ = 1.4 × 10-4 sec-1 ,H = 20 cm, and κ = 3 × 10-6 emu, the coupling coefficient comes out only of the order of 10-6 , as against unity in the case of the dynamo theory.