The Toroidal Magnetic Field inside the Sun

Abstract

Analysis of the fine structure of the solar oscillations has enabled us to determine the internal rotation of the Sun and to estimate the magnitude of the large-scale magnetic field inside the Sun. According to the data of Duvall et al. (1984), the core of the Sun rotates about twice as fast as the solar surface. Recently have showed that there is a sharp radial gradient in the Sun's rotation at the base of the convection zone, near the boundary with the radiative interior. It seems to us that the sharp radial gradients of the angular velocity near the core of the Sun and at the base of the convection zone, acting on the relict poloidal magnetic field B r , must excite an intense toroidal field B^, that can compensate for the loss of the magnetic field due to magnetic buoyancy.Magnetic buoyancy plays the main role in constraining the amplitude of the magnetic induction of the toroidal field generated at the present stage of solar evolution (Dudorov et al., 1989;Krivodubskij, 1990). There, from the condition of stationarity, dB^/dt -0, neglecting ohmic dissipation, we obtained the following expression for the maximum value of the established stationary toroidal field (Dudorov et a/., 1989;Krivodubskij, 1990):Here Aui is the increament in the angular velocity over the step Ar along the solar radius; P e is the electron pressure; UT is the mean velocity of upward transport of thermal energy; L is the space scale of the magnetic field; a is the transverse radius of the magnetic flux tube; A is the temperature scale height; r is the distance from the centre of the Sun. Krivodubskij (1990) performed an analysis of the energetic aspects of the problem. The total magnetic energy of the excited toroidal field, E* H = EHVH (EH = -B?/87r is the magnetic energy density), cannot exceed the total kinetic energy of the rapidly rotating core, E^. To make E H < £ £ , toroidal field with , available at https://www.cambridge.org/core/terms. https://doi