Comparative Analysis of Oscillations of a Solar Quiet Region Using Multi-Wavelength Observations

We analyze the temporal behavior of a solar quiet region using a set of multi-wavelength observations obtained during a coordinated campaign. The observations were acquired by the ground-based Dutch Open Telescope (DOT), the Michelson Doppler Imager (MDI) on-board SOHO and the UV filters of the Transition Region and Coronal Explorer (TRACE). A large range of height in the solar atmosphere, from the deep photosphere to the upper chromosphere is covered by these instruments. We investigate the oscillation properties of the intensities and velocities in distinct regions of the quiet Sun, i.e. internetwork, bright points (NBP) defining the network boundaries and dark mottles forming a well-defined rosette, as observed by the different instruments and in the different heights. The variations of the intensities and velocities are studied with wavelet analysis. The aim of our work is to find similarities and/or differences in the oscillatory phenomena observed in the different examined regions, as well as comprehensive information on the interaction of the oscillations and the magnetic field. 1. Observations Results We use a time series of Hα filtergrams (λ6563 A, at 5 wavelengths: ±0.35 A, ±0.7 A and line center) as well as CaII H (λ3968 A) and G–band (λ4305 A) observations of a quiet solar region, obtained by the Dutch Open Telescope (DOT, see Rutten et al. (2004) for details). Subtracting the intensity of red and blue wings we create Doppler Signal (D.S.) maps, at±0.7 A and±0.35 A from line center, which provide a qualitative measure of the velocity. We also use co–temporal and co–spatial TRACE observations at the UV continua (1550 A, 1600 A and 1700 A). MDI, onboard SoHO provided high resolution line-of-sight magnetograms. The cadence of our observations is 30 s and the duration of the part used here is 30min. We created 2-D maps of the average global wavelet power (Torrence & Compo (1998)), in three period bands centered at 3, 5 and 7min (Fig. 1). In G–Band, NBP’s appear bright in the 3min power maps. In TRACE continua there is suppression of the 3min and 5min power above the network, also visible in the CaII H maps. At Hα line center and wings, the power of the oscillations has a