Dynamics of the quiet upper solar atmosphere in the network
Gömöry P.1, Rybák J.1, Kucera A.1, Curdt W.2, Wöhl H.3
1 Astronomical Institute of the Slovak Academy of Sciences,
SK-05960 Tatranská Lomnica, Slovakia
2 Max-Planck-Institut für Sonnensystemforschung, D-37189 Katlenburg-Lindau, Germany
3 Kiepenheuer-Institut für Sonnenphysik, D-79104 Freiburg, Germany
Abstract:
The temporal evolution of the spectral parameters of the
chromospheric He I 584.33 A and the transition region O V 629.73 A emission
lines measured by the Coronal Diagnostic Spectrometer (CDS) in/above the supergranular network near
disk center was constructed in order to examine the correlation of the spectral line intensities
and the Doppler shifts. The arithmetic process of the correct calculation
of the cross-correlation function is shown here in details. The necessity of edge data removal
and the subtraction of any background trends before applying the cross-correlation
function was revealed. The method was verified using the test example of two ideal sinusoidal
functions.
Resulting cross-correlation functions were analyzed with a view to
describe energy transfer and mass motion between chromosphere and transition region
in the particular network.
The maximum value (CC = 0.46) of the cross-correlation function of the
He I and the O V line intensities was achieved for a time lag of +27.3 s, i.e.
some changes in the O V line intensities precede changes in the He I line intensities.
In contrast, the cross-correlation function of the Doppler shifts of these lines
reached the maximum value (CC = 0.53) for a time lag of 0 seconds.
In summary, we can assume that the non-radiative energy was transported
from the transition region down to the chromosphere without any significant
mass motion in the studied network element.