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  • THE SOURCE OF 3 MINUTE MAGN...
    Jess, D B; DE MOORTEL, I; Mathioudakis, M; Christian, D J; Reardon, K P; Keys, P H; Keenan, F P

    The Astrophysical journal, 10/2012, Volume: 757, Issue: 2
    Journal Article

    We use images of high spatial, spectral, and temporal resolution, obtained using both ground- and space-based instrumentation, to investigate the coupling between wave phenomena observed at numerous heights in the solar atmosphere. Analysis of 4170 A continuum images reveals small-scale umbral intensity enhancements, with diameters ~0".6, lasting in excess of 30 minutes. We find a maximum waveguide inclination angle of approximately 40degrees between photospheric and chromospheric heights, combined with a radial expansion factor of <76%. Derived kinetic temperature and emission measure time series display prominent out-of-phase characteristics, and when combined with the previously established sub-sonic wave speeds, we conclude that the observed EUV waves are the coronal counterparts of the upwardly propagating magnetoacoustic slow modes detected in the lower solar atmosphere. Thus, for the first time, we reveal how the propagation of 3 minute magnetoacoustic waves in solar coronal structures is a direct result of amplitude enhancements occurring in photospheric UDs.