Magneto-static Modeling from Sunrise/IMaX: Application to an Active Region Observed with Sunrise II
Abstract
Magneto-static models may overcome some of the issues facing force-free magnetic field extrapolations. So far they have seen limited use and have faced problems when applied to quiet-Sun data. Here we present a first application to an active region. We use solar vector magnetic field measurements gathered by the IMaX polarimeter during the flight of the Sunrise balloon-borne solar observatory in 2013 June as boundary conditions for a magneto-static model of the higher solar atmosphere above an active region. The IMaX data are embedded in active region vector magnetograms observed with SDO/HMI. This work continues our magneto-static extrapolation approach, which was applied earlier to a quiet-Sun region observed with Sunrise I. In an active region the signal-to-noise-ratio in the measured Stokes parameters is considerably higher than in the quiet-Sun and consequently the IMaX measurements of the horizontal photospheric magnetic field allow us to specify the free parameters of the model in a special class of linear magneto-static equilibria. The high spatial resolution of IMaX (110-130 km, pixel size 40 km) enables us to model the non-force-free layer between the photosphere and the mid-chromosphere vertically by about 50 grid points. In our approach we can incorporate some aspects of the mixed beta layer of photosphere and chromosphere, e.g., taking a finite Lorentz force into account, which was not possible with lower-resolution photospheric measurements in the past. The linear model does not, however, permit us to model intrinsic nonlinear structures like strongly localized electric currents.
- Publication:
-
The Astrophysical Journal Supplement Series
- Pub Date:
- March 2017
- DOI:
- 10.3847/1538-4365/aa582f
- arXiv:
- arXiv:1701.01458
- Bibcode:
- 2017ApJS..229...18W
- Keywords:
-
- Sun: chromosphere;
- Sun: corona;
- Sun: magnetic fields;
- Sun: photosphere;
- Astrophysics - Solar and Stellar Astrophysics
- E-Print:
- Accepted for APJS, Sunrise special issue