General information

Bd-monitoring is a daily full solar disk magnetogram processing system. The main product of this system includes daily full Br-maps of the photospheric radial magnetic field, and equivalent (in regard to the information content) sets of harmonic expansion coefficients of a current magnetic field. These data can be used in the analysis of a current three-dimensional magnetic structure of the solar corona

The acquisition of Br-maps is based on the technique described in a paper by G.V. Rudenko, Extrapolation of the solar magnetic field within the potential-field approximation from full-disk magnetograms: 2001, Solar Phys, 198, 5. This system uses a potential-field model of the magnetic field (the potential field-source surface (PFSS)) [Schatten, K. H.: 1971, Cosmic Electrodyn., 2, 232; Altschuler, M.D., and Newkirk, G.: 1969, Solar Phys., 9, 131].

Kitt Peak daily medres magnetograms (KPNO medres mag), and daily synoptic magnetograms (KPNO synoptic mag) are used as input data.

Results are placed in two sections of Calculated data: In these sections, results of calculations are placed in ten files for each Kitt Peak daily magnetogram (first section), and for each Kitt Peak daily synoptic magnetogram (second section): The Current images section accommodates images representing a current state of the magnetic structure. Images in the pages Br-maps (Photosphere), Smooth Br-maps (Photosphere), Smooth Bl-maps (Photosphere) , Smooth Br-maps (Source Surface), Smooth Br-maps (Source Surface, radial correction, Rs=2.5) and Smooth Br-maps (Source Surface, radial correction, Rs=3.25) are constructed from fits-files of the sections Bd-synoptic and Synoptic. The values of the contours are taken to be: -20., -10, -5, -1, 0, 1, 5, 10,20] Gs - at the photosphere, [-0.1,-0.05, -0.01, 0, 0.01, 0.05, 0.1, 0.2] Gs on the source surface R=2.5, and [-0.1, -0.05,-0.025, -0.005, 0.00, 0.005, 0.025, 0.05, 0.1]Gs on the source surface R=3.25. The two variants of "radial" correction are intended for improving the neutral line on the source surface. Corrections are carried out through a transformation of the Bl-component to a radial one (by diving by the cosine of latitude) prior to calculating the weight coefficients from Br. The difference from similar calculations from WSO data is merely that Bl is taken not from observational data but is obtained as a result of a preliminary reconstruction of the magnetic field. Calculations for a quiet period of solar activity show a very good agreement of the neutral lines corrected here with WSO neutral lines. One example of such a correspondence is illustrated on page Current Images 20/08/95.

The Holes ˝section contains a current calculation of regions of open field lines, and of their physical characteristics, based on data such as Bd-synoptic. The field lines are calculated from uniformly distributed (at steps of 40) on the source surface) start point. Their bases are shown in different colors for different open regions. The designations are:

The physical values of energies and magnetic fluxes can be obtained by multiplying by R3Sol[sm3] and R2Sol[sm2],respectively.

The system generates new data, and updates current images (except for Holes) about every 2-3 hours after the appearance of a new daily magnetogram in the Kitt Peak catalog. A further about 8 hours are required for updating Holes.

Currently the proposed version should be regarded as a preliminary one. Information that is generated by the system at this stage requires a still greater comparative analysis before any conclusive inference is made concerning the degree of its correspondence to the present physical picture of the dynamics of the solar magnetic structure. It is not yet fully clear how substantial would be the underlying approximations associated with the uncertainty of data for the far side in the main. Without such an analysis, however, we can be confident in the correctness of calculations spanning the heights on the order of the solar radius above the visible side of the disk. These issues were discussed at length in a paper of G.V. Rudenko: 2001, Solar Phys, 198, 5. A further analysis and comparison of results will, perhaps, choose a corrective addition that is appropriate for the boundary conditions for the Bd-component used here. I will greatly appreciate having any information that would be useful for a further development of this system. With all questions concerning the operation of the system please apply to George Rudenko.

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