Modeling and Interpreting the Effects of Spatial Resolution on Solar Magnetic Field Maps |
|
K.D. Leka Submitted: 2011-10-18 21:45
Different methods for simulating the effects of spatial resolution onmagnetic field maps are compared, including those commonly used forinter-instrument comparisons. The investigation first uses synthetic data, andthe results are confirmed with {it Hinode}/SpectroPolarimeter data. Fourmethods are examined, one which manipulates the Stokes spectra to simulatespatial-resolution degradation, and three 'post-facto' methods where themagnetic field maps are manipulated directly. Throughout, statisticalcomparisons of the degraded maps with the originals serve to quantify theoutcomes. Overall, we find that areas with inferred magnetic fill fractionsclose to unity may be insensitive to optical spatial resolution; areas ofsub-unity fill fractions are very sensitive. Trends with worsening spatialresolution can include increased average field strength, lower total flux, anda field vector oriented closer to the line of sight. Further-derived quantitiessuch as vertical current density show variations even in areas of high averagemagnetic fill-fraction. In short, unresolved maps fail to represent thedistribution of the underlying unresolved fields, and the 'post-facto' methodsgenerally do not reproduce the effects of a smaller telescope aperture. It isargued that selecting a method in order to reconcile disparate spatialresolution effects should depend on the goal, as one method may better preservethe field distribution, while another can reproduce spatial resolutiondegradation. The results presented should help direct future inter-instrumentcomparisons.
Authors: K.D. Leka, Graham Barnes
Projects: Hinode/SOT
|
Publication Status: Solar Physics, in press. doi: 10.1007/s11207-011-9821-7
Last Modified: 2011-10-19 09:21
|
 
 
|
|
|
Key
|
 | Go to main E-Print page. |
 | Download Preprint. |
 | Submitters Homepage. |
 | Edit Entry. |
 | Delete abstract. |
|
|
|