THE EVERSHED EFFECT IN PENUMBRAL FINE-STRUCTURES .2. SPATIAL CORRELATION-ANALYSIS

Spatially high resolved spectra of sunspot penumbrae were taken simult aneously in a number of lines with negligible Zeeman splitting. The fo rmation layers of the different lines span the entire height of the pe numbral photosphere. The intensity and velocity fluctuations from thes e different levels were subject to a spatial coherence and phase analy sis which yields the following results: a) Spectra with a spatial reso lution of at least 0.5 arcsec are necessary to detect a perfect correl ation between dark penumbral structures and wing shifts of lines emerg ing from deep layers near the continuum level. b) This correlation rap idly decreases towards higher levels in the penumbra; it almost disapp ears near the temperature minimum. c) The correlation increases when t he velocity fluctuations are compared with intensity fluctuations of t he corresponding residual intensities of the line cores rather than wi th the continuum intensity emerging from much deeper layers. d) The li ne asymmetry ends abruptly with the penumbral continuum depression thu s suggesting an interpretation of a causal relation with die penumbral fine structure. e) If Doppler shifts occasionally occur outside the w hite light penumbral border, the corresponding line profiles are symme tric and do not show a significant dependence on the formation height.