Implications of a strongly peaked polar magnetic field

✍ Scribed by N. R. Sheeley; Y. -M. Wang; C. R. DeVore

• Publisher: Springer
• Year: 1989
• Tongue: English
• Weight: 755 KB
• Volume: 124
• Category: Article
• ISSN: 0038-0938
• DOI: 10.1007/bf00146515

✦ Synopsis

Using the flux-transport equation in the absence of sources, we study the relation between a highly peaked polar magnetic field and the poleward meridional flow that concentrates it. If the maximum flow speed v,, greatly exceeds the effective diffusion speed K/R, then the field has a quasi-equilibrium configuration in which the poleward convection of flux via meridional flow approximately balances the equatorward spreading via supergranular diffusion. In this case, the flow speed v(O) and the magnetic field B(O) are related by the steady-state approximation v(O) ~-(rc/R)B'(O)/B(O) over a wide range of colatitudes 0 from the poles to midlatitudes. In particular, a general flow profile of the form sin p 0 cos q 0 which peaks near the equator (q ~ p) will correspond to a cos ~ 0 magnetic field at high latitudes only if p = 1 and v m = n ~c/R. Recent measurements of n ~ 8 and ~ ~ 600 km 2 s -1 would then give vm ~ 7 m s -1.