Estimation of the flux tube diameters outside sunspots using Hinode observations. Preliminary results

Abstract

Indirect estimations of diameters of the smallest flux tubes outside sunspots are made using SOT/Hinode observations of Fe I 6301.5 and 6302.5 lines. These estimations are based on the comparison of measured effective magnetic field strength B_{eff} in named lines. It is shown that B_{eff}(6301.5)/B_{eff}(6302.5)≈ 1.3 in the range B_{eff}=40-300 G, and B_{eff} (6301.5)/B_{eff}(6302.5)≈.0 for B_{eff}≤10-20 G. The first case corresponds to the two-component magnetic field with kG flux tubes and weak background field, whereas the second one corresponds to background field without flux tubes. Assuming that the field range B_{eff}=10-40 G corresponds to the case with only one flux tube in each pixel, the flux tube diameters should be 15-30 km. Possible influence of the brightness contrast and the Zeeman saturation could change this estimation by approximately 20%.