On Green Corona Rotation

Rybak J.

Astronomical Institute, 059 60 Tatranská Lomnica, The Slovak Republic

The solar emission corona rotation was determined using Fe XIV 530.3 nm coronal line measurements for the epoch 1947-1991 via the tracer method. The optimized correlation analysis has been applied together with a new reliability test for determination of rotation. Time-latitudinal dependence of the green corona rotation on the phase of the solar cycle shows nearly rigid latitudinal behaviour for few years before and during cycle minima and it is rapidly changing to a differential rotation just after the onsets of the solar cycle. This differential rotation profile prolongs up to the beginning of the descending phase of the cycle and then a slow return to the rigid profile follows. Large variations of green corona rotation between these two extremes lead to the conclusion that the overall latitudinal and temporal averages of coronal rotation are not physically correct.