Abstract
We present speckle observations of small-scale magnetic structures on the Sun. They were obtained with the GottingenFabry-Perot interferometer (FPI) in the Vacuum Tower Telescope at the Observatorio del Teide, Tenerife, from quiet and active regions close to disc center. A Stokes V polarimeter was added to the FPI to measure V profiles in the Fe I 6302.5 Aline. The setup allows image reconstruction with speckle methods. The achieved spatial resolution in the magnetograms is -. We describe the observational technique and the data reduction. The results from small-scale magnetic flux elements in a very quiet region, in an active region with pores and abnormal granulation, and in a sunspot with its surroundings are discussed. In the quiet Sun, granular dynamics dominate the time evolution of the magnetic elements. Flux occurs in both bright intergranular points and in dark intergranular spaces. Likewise, with the present spatial resolution, no preference of magnetic flux in abnormal granulation in an active region can be found. Flux occurs in both bright (abnormal) small-scale granules and in the darker spaces in between them. The small sunspot studied has very little magnetic flux in its ambient quiet regions, especially no strong, conspicuous concentrations of returned flux, i.e. of flux with polarity opposite to that in the sunspot.
Highlights
Magnetic fields are important constituents of the solar atmosphere on all scales
They were obtained with the “Gottingen” Fabry-Perot interferometer (FPI) in the Vacuum Tower Telescope at the Observatorio del Teide, Tenerife, from quiet and active regions close to disc center
A broader discussion of, e.g., profile asymmetries and relationships between intensity, velocity, and magnetic fields at high spatial resolution is prepared for a forthcoming contribution
Summary
Magnetic fields are important constituents of the solar atmosphere on all scales. Their interaction with the solar plasma causes the magnetic heating of the chromosphere and the corona and is responsible for all processes of activity from the low photosphere to the solar wind. Beckers & Schroter (1968) have found “magnetic knots” in the neighbourhood of sunspots as well as in quiet regions of the Sun. From the line ratio method, i.e. the use of two spectral lines which differ in their properties only by their Lande factor, Stenflo (1973) could conclude on the existence of kilo-Gauss fields with a small fill factor in the observed area. Keller & von der Luhe (1992) have used broad-band speckle polarimetry to measure the circularly polarized light components The spectrometer scans along wavelength and gives narrow-band images across spectral lines This allows to apply image reconstruction techniques and to substantially reduce the deteriorations by seeing (see e.g. Krieg et al 1998, 1999).
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