ZIMPOL

Differential Hanle effect and the spatial variation of turbulent magnetic fields on the Sun

While diagnostic techniques based on the ordinary Zeeman effect (e.g. magnetograms) are almost ``blind'' to a turbulent magnetic field with mixed magnetic polarities within the spatial resolution element, the Hanle effect is sensitive to this domain …

The second solar spectrum. A new window for diagnostics of the Sun.

The Sun's radiation becomes linearly polarized by coherent scattering processes in the solar atmosphere. With a novel polarimetry system that achieves a precision of 1e-5 in the degree of polarization, the previously largely unexplored territory of …

Observations of the quiet Sun's magnetic field.

The profiles of Stokes I and V of FeI 5247A, CrI 5247A, FeI 5250.2A and Fe I 5250.6A have been measured in the quiet photosphere with ZIMPOL, a new polarimeter, with very low noise level. The spatial resolution element of about 1Mm was essentially …

Imaging Coronal Emission Lines under High Sky-Background Conditions

We have obtained images in solar coronal emission lines under high sky- background conditions by making precise differential measurements between the coronal emission line and the near-by continuum, which is primarily due to scattered light from the …

Measurement of the full Stokes vector of He I 10830 ̊A

First observations of the full Stokes vector in the upper chromosphere are presented. The He I 10830 ̊A line, which has been shown to give reliable measurements of the line-of-sight component of the magnetic field vector, has been used for this …

Recent Progress in Imaging Polarimetry

Recent instrumental developments in imaging polarimetry allow array detectors to reach a polarimetric sensitivity of 1 × 10$^-4$ of the intensity. New instrumental effects appear at these levels of sensitivity and generate spurious polarization …

On the strength of solar intra-network fields.

The combination of the German Vacuum Tower Telescope and the prototype of ZIMPOL I (Zuerich Imaging Stokes Polarimeter I), a novel, very sensitive imaging polarimeter, has resulted in the first spectra of solar intra-network (IN) fields in circular …