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A Program Complex Equipped With a GUI for Investigation of 3D Structure of Solar Magnetic Fields Next: Xguiphot: A New Aperture Photometry Tool for IRAF
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Rudenko, G. V. & Grechnev, V. V. 1999, in ASP Conf. Ser., Vol. 172, Astronomical Data Analysis Software and Systems VIII, eds. D. M. Mehringer, R. L. Plante, & D. A. Roberts (San Francisco: ASP), 421

A Program Complex Equipped With a GUI for Investigation of 3D Structure of Solar Magnetic Fields

G. V. Rudenko, V. V. Grechnev
Institute of Solar-Terrestrial Physics, Lermontov St. 126, Irkutsk, Russia 664033, Email: rud@iszf.irk.ru

Abstract:

A program packet is developed for the detailed research into the 3D structure of the magnetic fields of solar active regions as well as the overall solar magnetic field. The application realized in the IDL program environment is supplied with the graphical user interface (GUI) which ensures convenient and efficient manipulation with data.

1. Introduction

Solar activity is the result of motion and interaction of the coronal magnetic fields, so their study is of primary interest of solar physicists. We have developed a program packet for the detailed research into the 3D structure of the magnetic fields of solar active regions as well as the overall solar magnetic field.

The work with data includes two stages. On the first step, coefficients of decomposition are calculated for a selected magnetogram and recorded into special ``weight'' files. Then the viewing and processing of data after those coefficients is made using an application supplied with graphical user interface (GUI). The application is developed in the IDL1 program environment.

2. Calculation of the coefficients of decomposition

2.1 Source data

Initial data are taken from daily magnetograms of arbitrary regions on the visible side of the solar disk, and synoptic magnetograms. On their basis, coefficients of decomposition are calculated.

Input data for the GUI-supplied application are the special files containing weight coefficients:

Those ``weight files'' are computed and recorded separately by another FORTRAN program.

2.2 Initial mathematical statements of boundary-value problems to be solved


a) for the reconstruction of partial frames:
$\nabla \times {\bf B}=\alpha {\bf B}$ + boundary conditions of the magnetic component
$\nabla {\bf B}=0$   along the line of sight (Bd) at the photopsheric level
    (at each point);
     
b) for the reconstruction of the whole surface of the Sun:
${\bf B}=-\nabla \phi $ + boundary conditions of the magnetic component along the
$\Delta \phi =0$   line of sight (Bl) at the photopsheric level at the instant
    of passage of a point across the central meridian.

In the former case, it is possible to select the constant $\alpha $ of the force-free approximation. In the latter case, only the potential approximation is used.

The calculations of the coefficients of the plane decomposition are based on a new method (Rudenko, Altyntsev, & Lubyshev 1997) which allows, unlike the traditional ones, to reconstruct the magnetic field above small regions according to photospheric magnetic fields which are observed in an arbitrary site on the solar disk. In fact, it is possible to use the magnetographic data on active regions which are located close to the limb. This latter circumstance extends opportunities to study magnetic fields of active regions and the evolution while they passing across the solar disk.

The coefficients of decomposition are calculated from magnetograms. Magnetograms of separate active regions can also be processed. Precise scaling and positioning to fit the working coordinate system is accomplished automatically and can also be made in the interactive mode, as well as selection of a region of interest. Data of other types can be used.

3. GUI-supplied application

The program packet was developed in the IDL program environment. The program has GUI (Fig. 1) and provides the following facilities:

Figure 1: A screen dump of the GUI-supplied application.
\begin{figure} \epsscale{1.0} \plotone{rudenkogv1.eps} \end{figure}

The program code has been checked under MS Windows 95 and UNIX with IDL versions since 3.0.1 to 5.1.

4. Conclusion

We consider a possibility to make calculations of magnetic fields for particular active regions after requests through Internet. In this case, files containing coefficients of decomposition would be calculated by our FORTRAN programs and made available.

We plan to develop a data bank and to supply it with files on the known active regions in the future.

Acknowledgments

We are indebted to Dr. D. Stern (Research systems, Inc.) for his assistance in familiarizing IDL 5.0. We are grateful to the ADASS'98 conference for the financial aid which has made possible the attendance of the authors at the conference. We are indebted to Mr. V. Mikhalkovsky (ISTP) for his assistance in preparation of English version of the text. This work was supported by grant of Russian Foundation RFFI.

Magnetograms which we use are produced by NSO/Kitt Peak in collaboration with NSF/NOAO, NASA/GSFC and NOAA/SEL.

References

Rudenko, G. V., Altyntsev, A. T., & Lubyshev, B. I. 1997, in Ann. Rep. of Joint Organization for Solar Observations, ed. A. Antalova & A. Ku{\v{c\/}}era, 94


Footnotes

... IDL1
IDL is the trademark of Research Systems, Inc.
© Copyright 1999 Astronomical Society of the Pacific, 390 Ashton Avenue, San Francisco, California 94112, USA
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