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Schematic of the Solar Dynamo

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posted on 2012-12-05, 10:22 authored by Paul HigginsPaul Higgins

    This is a schematic of the solar hydro-magnetic dynamo. This image is a cut-away of the solar interior. The dashed lines indicate the surface of the Sun (photosphere) and the base of the convection zone (tachocline). The colors show the rate of rotation within the Sun (helioseismology results taken from: Howe, 2009; link provided bellow), where differential rotation occurs in the convection zone (the sun rotates faster near the equator than at the poles). Beneath the convection zone the Sun rotates as a solid body. 

     The magnetic field of the Sun at solar minimum is a dipole (polar, in orientation) and over time, differential rotation shears the magnetic fields at the tachocline, dragging them along the equator, into a toriodal configuration. As these magnetic fields become sheared, and twisted, and they grow in strength, becoming magnetic "flux-ropes". When their fields are strong enough, "magnetic buoyancy" becomes important and causes them to begin to rise through the convection zone toward the solar surface.

     The third panel shows the situation as the Sun approaches the maximum of the solar cycle, when flux-ropes are emerging at the solar surface, causing the solar magnetic field to become multpolar. 

This image appeared in my thesis defense (viva) presentation.