On the Discrepancy of Coronal Magnetic Fields in Solar Optics and Radio

It is analysed the discrepancy about the coronal magnetic eld between solar optic and solar radio using magnetic bril concept with lling factor and fractal structure model. The magnetic eld of 100 G considered in solar optics is mean value in a large scale, and that of 1000 G in solar should be the value of ne structures inside \macro" loop. The magnetic eld in the solar corona is poorly known because there are few kinds of observations that can measure it unambiguously (Gary et al.1993). It is contentious about the coronal magnetic elds in solar optics and radio. In solar optics, the magnetic eld is usually considered as 100 G, many measurements indicate that few or no prominences have eld strengths above 150 G, and typical strengths are 26 G (Harvey 1969); in solar radio, it is always takens as 1000 G to t the observed emission ux, Peterson and Winck-ler (1959) took the eld strength of 1000 G in calculating the number of fast electrons in the solar are, Holt and Cline (1968) and Holt and Ramaty (1969) used numerical calculations of gyrosynchrotron emis-sivity to estimate the number of electrons for the are of gyrosynchrotron emissivity to estimate the number of electrons for the are of 1966 July 7, and deduced the eld strength is 1000 G, De Feite (1975) made a rough estimate and obtained a typical source eld strength of 1200 G for solar are. By observation, Gary et al. (1993) deduced that the magnetic eld strength at the base of the corona above the leading spots was 1200 G, and 1100 G above the folling spots. Now it is known that there are observed small-scale magnetic elds on the solar surface, perhaps the sunspots contain complex internal ne structure that are far from being fully resolved. It is believed that these magnetic structures are composed of many thinner uxtubes (De Jager et al. 1993), for convenience called magnetic brils. The corona is highly inhomoge-neous, many observations suggest such a structure in the solar corona. Several authors (De Jager 1986) have found that magnetic loops on the sun are not homogeneously lled with magnetic elds but that there is a lling factor being 1; De Jager (1986) had summarized data available at that time and concluded to averge values of 0.01. It is proposed that the gas is limited to a number of very thin magnetic …