We report new properties of solar magnetic fields in a quiet region as found from their magnetic power spectra. The power spectra of network and intranetwork fields (non-network fields) are separately calculated from a Big Bear magnetogram obtained with moderately high spatial resolution of 1.5 arc sec and a high sensitivity reaching 2 Mx cm-2. The effect of seeing on the power spectrum has been corrected using Fried's (1966) Modulation Transfer Function with the seeing parameter determined in our previous analysis of the magnetogram. As a result, it is found that the two-dimensional power spectra of network and non-network fields appear in a form: Γ(k0 ≲ k ≲ k1) ∼ k-1 and Γ(k ≳ k1) ∼ k-3.5. Here k0 ≈0.47 Mm-1 for network fields and k0 ≈0.69 Mm-1 for non-network fields, the latter of which corresponds to the size of mesogranulation; k1 ≈ 3.0 Mm-1 for both, which is about the size of a large granule. The network field spectrum below k0 appears nearly flat, whereas that of non-network fields instead decreases towards lower wave numbers as Γ(k) ∼ k1.3. The turnover behavior of magnetic field spectra around k1 coincides with that found for the velocity power spectrum, which may justify the kinetic approach taken in previous theoretical studies of the solar magnetic power spectra.
All Science Journal Classification (ASJC) codes
- Astronomy and Astrophysics
- Space and Planetary Science