ON THE DISTRIBUTION OF THE SOLAR MAGNETIC-FIELDS

This paper reports a study of the distribution of the solar magnetic field using the two magnetically sensitive infrared Fe I lines at 15648 Angstrom and 15652 Angstrom. We scanned the spectrograph slit across the solar surface (both active and quiet regions) to obtain three-dimensional data cubes (two spatial dimensions and one spectral dimension). Using the full Stokes V profiles, we can measure the true magnetic field strength the size, and the magnetic flux of magnetic elements simultaneously. The major findings of this observation can be summarized as follows: 1. We made the first direct Zeeman splitting measurement of the intranetwork elements. The average field strength of the intranetwork elements with a magnetic flux above 1.5 x 10(16) Mx per pixel is approximately 500 G. 2. To the first-order approximation, the surface magnetic field distribution can be described by a two-component model. The first component is the strong-field component. It has an average field strength of approximately 1400 G and is found in the sunspots, plages, and network elements. The second component has intrinsically weaker field strength, typically around 500 G. It is found mostly in the intranetwork magnetic elements. 3. The average size of the weak-held elements is approximately 70 km in diameter. We suggest that the strong-field component represents the large-scale, deeply rooted solar cycle field, and the weak-field component originates in the solar convection zone, and may be generated from the turbulent velocity field by mixing and dispersion of floating strong flux tubes (U-loops) (Spruit, Title, and Van Ballegooijen 1987), and as a small-scale dynamo (Petrovay and Szakaly 1993; Durney, De Young, and Roxburgh 1993). We propose that the strong- and weak-field components are supported by the thermal and turbulent pressure of the solar photosphere, respectively.