Resolving the Azimuthal Ambiguity in Vector Magnetogram Data with the Divergence-Free Condition: Application to Discrete Data
arXiv:0911.0711 · doi:10.1007/s11207-009-9454-2
Abstract
We investigate how the divergence-free property of magnetic fields can be exploited to resolve the azimuthal ambiguity present in solar vector magnetogram data, by using line-of-sight and horizontal heliographic derivative information as approximated from discrete measurements. Using synthetic data we test several methods that each make different assumptions about how the divergence-free property can be used to resolve the ambiguity. We find that the most robust algorithm involves the minimisation of the absolute value of the divergence summed over the entire field of view. Away from disk centre this method requires the sign and magnitude of the line-of-sight derivatives of all three components of the magnetic field vector.
Solar Physics, in press, 20 pages, 11 figures
References in corpus (1)
Cited by in corpus (9)
- Analysis of a Fragmenting Sunspot using Hinode Observations
- Distinguishing between Flaring and Non-Flaring Active Regions: A Machine Learning Perspective
- Comment on "Resolving the 180-deg Ambiguity in Solar Vector Magnetic Field Data: Evaluating the Effects of Noise, Spatial Resolution, and Method Assumptions"
- Response to "Comment on `Resolving the 180deg Ambiguity in Solar Vector Magnetic Field Data: Evaluating the Effects of Noise, Spatial Resolution, and Method Assumptions'"
- Resolving the Azimuthal Ambiguity in Vector Magnetogram Data with the Divergence-Free Condition: the Effects of Noise and Limited Spatial Resolution
- Resolving the Azimuthal Ambiguity in Vector Magnetogram Data with the Divergence-Free Condition: Implementations for Disambiguating Each Height Independently
- Magnetic Field Structures in a Facular Region Observed by THEMIS and Hinode
- Magnetometry: solving the fundamental ambiguity from line pair inversion
- Least-Squares Fitting Methods for Estimating the Winding Rate in Twisted Magnetic-Flux Tubes