Resolving the 180° Ambiguity in Solar Vector Magnetic Field Data: Evaluating the Effects of Noise, Spatial Resolution, and Method Assumptions

By K. Leka, G. Barnes, A. Crouch, T. Metcalf, G. A. Gary, J. Jing, Yang Liu. 2009

262 citations recorded by the source corpus.

Subfields: Artificial Intelligence, Astronomy and Astrophysics, Molecular Biology

View Paper: https://www.semanticscholar.org/paper/39baeffc4a85e942bd6318eef67d6cd6c94dbc9e

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Citations in the corpus

Comparison of Line-of-Sight Magnetograms Taken by the Solar Dynamics Observatory/Helioseismic and Magnetic Imager and Solar and Heliospheric Observatory/Michelson Doppler Imager (2012, methodology): “The Stokes parameters [I, Q, U, V ] are computed from those measurements, and are further inverted (Borrero et al., 2011) and SOLA: hmilosmag_v0315.tex; 16 March 2012; 9:08; p. 2 disambiguated (Metcalf et al., 2006; Leka et al., 2009) to retrieve the vector magnetic field.”
The Helioseismic and Magnetic Imager (HMI) Investigation for the Solar Dynamics Observatory (SDO) (2012, methodology): “A further product is computed as the final vector field by applying a field direction disambiguation technique, since the Stokes parameters cannot distinguish the polarity of the component of the field normal to the line-of-sight (Metcalf, 1994; Metcalf et al., 2006; Leka et al., 2009).”
The Helioseismic and Magnetic Imager (HMI) Vector Magnetic Field Pipeline: Overview and Performance (2014, background): “This method has been shown to be among the best performing on a wide range of tests on synthetic data for which the answer is known (Metcalf et al., 2006; Leka et al., 2009).”
ELECTRIC CURRENTS IN FLARE RIBBONS: OBSERVATIONS AND THREE-DIMENSIONAL STANDARD MODEL (2014, methodology): “After the inversion, the 180◦ remaining azimuth ambiguity was resolved by applying the ME0 code developed by Metcalf, Leka, Barnes, and Crouch (Leka et al. 2009) and available at http://www.cora.nwra.com/AMBIG/.”
Solar Force-free Magnetic Fields (2012, methodology): “(2006) has been continued in Leka et al. (2009). The authors investigated the effects of Poisson photon noise and a limited spatial resolution. It was found that most codes can deal well with random noise and the ambiguity resolution results are mainly affected locally, but bad solutions (which are ”
The Helioseismic and Magnetic Imager (HMI) Vector Magnetic Field Pipeline: SHARPs – Space-Weather HMI Active Region Patches (2014, methodology): “• The azimuthal component of the vector magnetic field is disambiguated using the Minimum Energy Code (ME0) to resolve the 180◦ ambiguity (Metcalf, 1994; Leka et al., 2009).”
RESPONSE OF THE PHOTOSPHERIC MAGNETIC FIELD TO THE X2.2 FLARE ON 2011 FEBRUARY 15 (2011, methodology): “…pipeline1 to (1) retrieve the vector magnetic field using the Very Fast Inversion of the Stokes Vector (VFISV) algorithm (Borrero et al. 2010) based on the Milne-Eddington approximation, (2) resolve the 180◦ azimuthal ambiguity using the “minimum energy” method (Metcalf 1994; Leka et al. 2009).”
EVOLUTION OF MAGNETIC FIELD AND ENERGY IN A MAJOR ERUPTIVE ACTIVE REGION BASED ON SDO/HMI OBSERVATION (2011, methodology): “The 180◦ azimuthal ambiguity in the transverse field is resolved by an improved version of the “minimum energy” algorithm (Metcalf 1994; Metcalf et al. 2006; Leka et al. 2009).”
How Should One Optimize Nonlinear Force-Free Coronal Magnetic Field Extrapolations from SDO/HMI Vector Magnetograms? (2012, methodology): “The 180◦ azimuthal ambiguity in the transverse field is resolved by an improved version of the minimum energy algorithm (Metcalf, 1994; Metcalf et al., 2006; Leka et al., 2009).”