The magnetic field induced by the bodily tide in the core of the Earth.
The motion in the liquid core of the earth due to the bodily tide can induce a periodic magnetic field having the frequency sigma 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 sigmaH(2)/lambda, where H denotes the height of the equilibrium tide, and lambda = 1/4pikappa, kappa denoting the electrical conductivity of the core. With sigma = 1.4 x 10(-4) sec(-1), H = 20 cm, and kappa = 3 x 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.
Department of Applied Mathematics, The Weizmann Institute, Rehovot, Israel.
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