Fully resolved quiet-Sun magnetic flux tube observed with the Sunrise IMaX instrument

摘要

Until today, the small size of magnetic elements in quiet Sun areas hasrequired the application of indirect methods, such as the line-ratio techniqueor multi-component inversions, to infer their physical properties. A consistentmatch to the observed Stokes profiles could only be obtained by introducing amagnetic filling factor that specifies the fraction of the observed pixelfilled with magnetic field. Here, we investigate the properties of a smallmagnetic patch in the quiet Sun observed with the IMaX magnetograph on boardthe balloon-borne telescope Sunrise with unprecedented spatial resolution andlow instrumental stray light. We apply an inversion technique based on thenumerical solution of the radiative transfer equation to retrieve thetemperature stratification and the field strength in the magnetic patch. Theobservations can be well reproduced with a one-component, fully magnetizedatmosphere with a field strength exceeding 1 kG and a significantly enhancedtemperature in the mid- to upper photosphere with respect to its surroundings,consistent with semi-empirical flux tube models for plage regions. We thereforeconclude that, within the framework of a simple atmospheric model, the IMaXmeasurements resolve the observed quiet-Sun flux tube.