Phase Differences Between Intensity and Doppler Shift and Between Two EUV Emission Lines of Sill For 300 Second and 95 Second Chromospheric Oscillations

Extract

Phase differences between intensity and doppler shift in each of the two bright emission lines of Sill at λ1816.93, λ1817.45 are determined for chromospheric oscillations with periods near 300 seconds and 95 seconds. Phase differences between the oscillations in the two lines are determined also.

For the 300 second oscillation, maximum intensity most often leads maximum blue shift by about 40 seconds and the oscillation in the fainter line at λ 1817.45 most often leads the oscillation in the stronger line at λ 1816.93 by about 35 seconds. For the 95 second oscillation, maximum intensity most often lags maximum blue shift by about 20 seconds and the oscillations in the fainter line most often lags the oscillations in the stronger line by about 12 seconds.