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 FeI 6301.5 and 6302.5 lines. These estimations are based on the comparison of measured effective magnetic field strength Beff in named lines. It is shown that Beff(6301.5)/Beff(6302.5)≈1.3 in the range Beff=40-300 G, and Beff(6301.5)/Beff(6302.5)≈1.0$ for Beff≤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 Beff=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%.