Reconstruction of Local Magnetic Structures by a Modified Radial Basis Function Method

• Published in: Journal of geophysical research. Space physics Vol. 124; no. 12; pp. 10141 - 10152
• Main Authors: Chen, Wenming, Wang, Xiaogang, Tsyganenko, N. A., Andreeva, V. A., Semenov, V. S.
• Format: Journal Article
• Language: English
• Published: Washington Blackwell Publishing Ltd 01-12-2019
• Subjects: Clusters; Magnetic fields; magnetic null; Magnetic reconnection; Magnetometers; Radial basis function; Random errors; Reconstruction; reconstruction method; separator; Separators; Spacecraft; Three dimensional models; Topology
• DOI: 10.1029/2019JA027078
• EISSN: 2169-9402
• ISSN: 2169-9380

Local magnetic structures in space environments, in particular, those in the diffusion region such as magnetic nulls or separators, are very difficult to identify by satellite measurements but important for understanding of magnetic reconnection. Multi‐spacecraft missions such as Cluster or MMS, however, provide an opportunity to reconstruct the fine structures using vector data of space magnetometers. In this paper, we introduce a method for such a local reconstruction, based on the modified radial basis functions (Andreeva & Tsyganenko, 2016, https://doi.org/10.1002/2016JA023217), used previously for the global magnetic field modeling. A principal advantage of this method is its freedom from a priori assumptions on the magnetic field topology. The method has been tested on 21/2 and 3D reconnection geometries and provided a good agreement with preset models. The relative errors of null positions, γ‐line directions, and ∑‐surface normal directions are found to be below 6% even with 20% random errors added to the target magnetic field vectors in reconstruction of 3D separator model geometry. Applications of the method to the field reconstruction based on Cluster measurements are also presented and discussed.
Key Points
A new method based on radial basis function expanding is developed to reconstruct magnetic structures utilizing multi‐spacecraft data
Without prior imposed current sheet, the method can reconstruct the separator reconnection geometry comprised of two opposite polarity nulls