Conference paper or proceedings

Fine Scale, Rapid Dynamics of the Solar Atmosphere from Space-Based Versus Ground- Based Observations

We compare analyses of multi-wavelength, high-cadence sequences of high-resolution solar images that are derived from ground-based observations and from space-based observations. The original analyses aim to show the effects of magnetism on the propagation of wave energy from the photosphere into the solar atmosphere. Here we focus on differences that arise from the differing circumstances of the data acquisition. The ground-based data are a 9 hour sequence of Swedish Vacuum Solar Telescope filtergram images made on 1998 May 30 in the photospheric G-band and in the chromospheric CaII K-line with 21 s cadence. Atmospheric distortion was removed by phase diversity reconstruction, and the images were 4 x 4 square averaged to a spatial resolution of 0.24 Mm/px. A sequence of line-of-sight magnetograms had lesser resolution and longer cadence. The primary space-based data are a 6 hour sequence at 1 min cadence of Hinode SOT-FG images in G-band and CaII H-line and line-of-sight magnetic field, made on 2007 May 2. For space-based data phase reconstruction is irrelevant. The spatial scale is 0.08 Mm/px but can be averaged to lower resolutions. The relative phases of oscillations in the different data channels and the correlations between oscillation periods and spectral intensities show significant differences between the space- and ground-based cases. These differences may come partly from terrestrial atmospheric fluctuations that, in spite of phase reconstruction, act to artificially strengthen correlations among the ground-based data channels. For example, the photospheric and the chromospheric intensity fluctuations are more strongly correlated in the ground data than in the space data. The relative phases of oscillations in the three data channels show some different dependences on magnetic field strength between the two cases. This may be attributable to the higher quality of the available space magnetic data.

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