J. Rybák1,
A. Kucera1,
W. Curdt2,
H. Wöhl3
1Astronomical Institute of the Slovak Academy of Sciences,
SK-05960 Tatranská Lomnica, Slovakia
2Max-Planck-Institut für Sonnensystemforschung, D-37189 Katlenburg-Lindau, Germany
3Kiepenheuer-Institut für Sonnenphysik, D-79104 Freiburg, Germany
SUMER/SOHO measurements of the transition region C II 1037 A (30000K) and O VI 1031.9 A (280000K) emission lines in a distinctive network of the quiet solar atmosphere are used to search for consequences of the possible nanoflare heating of the corona. tistical analysis of the central line intensity and the line shift of these lines has revealed for the studied network: 1/ systematically larger values of the line shifts in the network relatively to internetwork; 2/ distinct dependence of the line shifts and on the line intensities (comparing to internetwork reference) in the form of separated 'clusters' of data coming from in the network and internetwork; 3/ no correlation between the line shifts and the line intensities in the network. A case study of the particular O VI spectral profiles has shown that at least some of the significantly broadened O VI line profiles consist in fact of two Gaussian profiles: one referring to a central less shifted component and the other to a weak more redshifted component. These findings are compared to results of other observational studies as well as to results of MHD simulations of the magnetic loops in the outer solar atmosphere in which the nanoflare heating mechanism was incorporated. Our preliminary results show that the derived observational facts are consistent with effects of fast magneto-acoustic modes, predicted to be caused by nanoflares, travelling downward along the loops in network. Nevertheless an agreement can be found only when spatial and temporal smearing of measurements are taken into account.
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