2009/10/26 by Ashley D. Crouch, A. D. Crouch, G. Barnes +2 · 1 citation
Computer Science · Physics and Astronomy · #Ambiguity #Azimuth #Divergence (linguistics) #Ionosphere and magnetosphere dynamics #Magnetic field #Magnetogram #Property (philosophy) #Sign (mathematics) #Solar Radiation and Photovoltaics #Solar and Space Plasma Dynamics #Vector field #astro-ph.SR
paper · pdf · doi:10.1007/s11207-009-9454-2
Solar Physics, in press, 20 pages, 11 figures
openalex publication_date 2009/10/26 · arxiv created 2009/11/03 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
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.