Astron. Astrophys. 347, L27-L30 (1999)

1. Introduction

The magnetic field of the sun is largely concentrated into features that resemble flux tubes (Stenflo 1994, Schüssler 1992, Solanki 1998) in the sense that they harbour most of the magnetic energy in photospheric layers. The cross-sectional area of individual flux tubes varies from an estimated of the area of the visible solar hemisphere (elements of the intranetwork field) to (sunspots), i.e. by over 6 orders of magnitude. These areas correspond roughly to diameters of 50 km to 70000 km. The magnetic flux carried by a flux tube also exhibits a similarly large range. However, the intrinsic field strength, B, of features with an estimated diameter km changes by less than a factor of two if averaged over the cross-section of the flux tube, as was first pointed out by Solanki & Schmidt (1993).

In this paper we look for additional similarities in the magnetic structure of such disparate features as magnetic elements and sunspots. In particular, we want to compare how the cross-sectional area of each evolves with height.

© European Southern Observatory (ESO) 1999

Online publication: June 30, 1999
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