Science Justification: The justification for our continued work is rooted in the need to examine the free energy in the magnetic field in the Sun's atmosphere. In particular, we wish to try to define the magnetic structure at the coronal base - the upper chromosphere - together with coronal plasma measurements themselves. The need to make measurements now is motivated not only by the availability of IBIS as a new spectropolarimeter but also because we wish to take advantage of the unique Hinode and TRACE observatories while they are still operating well.
Justification for additional time: We request a further 14 days of time with the DST/IBIS, combined with Hinode and TRACE, in each of the next two quarters. Of two allocated times for observations (May and December 2008), we were fortunate to obtain excellent quality data on just one day,20 May 2008, owing to atmospheric limitations. Unfortunately the overlap with the Hinode SOT data was only partial (50%), sampling only a small fraction of the region of activity and insufficient to examine reliably the magnetic fields. In this attempt, we hope to reach several new goals:
- First, to obtain complete overlap with the Hinode SOT and XRT instruments,
- second, to obtain vector magnetic field data of a small region of activity (small spot or pore) sufficient to capture most of the connections of magnetic field lines locally,
- third, and only under conditions of excellent seeing, to observe near or at the solar limb,
- fourth, to obtain at least one time series at fast (20s or faster) cadence in Halpha to explore further the dynamics of fibrils and their possibility to trace out magnetic lines of force,
- fifth, to assess the origin and mitigation of cross-talk between Stokes parameters observed with IBIS.