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%.