Constructing Solar Magnetic Power Spectra from MDI Magnetograms
J. Lee, J.-C. Chae, and H.S. Yun
We propose to obtain magnetograms of solar quiet regions using the MDI for
a purpose of studying properties of the photospheric fields in terms of
power spectrum. A power spectrum analysis of magnetic field distribution is
a powerful tool for quantifying and revealing the hierarchical nature of solar
magnetic fields. However, a main obstacle for achieving this goal has been that
the ground-based observations of solar magnetic fields are under the influence
of
atmospheric seeing which precludes accurate determination of the high wavenumber
regime of the power spectrum. Recently we (Lee et al. 1996) addressed this
problem
in detail using a deep magnetogram obtained at Big Bear Solar Observatory and a
carefully-determined Modulation Transfer Function (MTF) for the atmospheric
seeing.
We wish to carry out the same analysis using data obtained from MDI, for they
are
the most ideal for this problem. The fact that MDI magnetograms are free of the
atmospheric seeing contamination, together with its high sensitivity to weak
fields
in the photosphere, will permit a more accurate determination of spectral
morphology of the solar magnetic power spectrum than ever. Once data are
obtained,
analysis of the data can be performed in a straightforward manner with use of
our
softwares at hand.