Observation of the period ratio P_1/P_2 of transversal oscillations in solar macro-spicules

Abstract

We analyze the time series of oxygen line profiles (O vi 1031.93 A and O vi 1037.61 A obtained from SUMER/SOHO on the solar south limb. We calculated Doppler shifts and consequently Doppler velocities in three heights 4", 14", and 24" from the limb on a coronal hole region. Then, we performed wavelet analysis with Morlet wavelet transform to determine the periods of fundamental mode and its first harmonic mode. The calculated period ratios have departures from its canonical value of $2$. The density stratification and magnetic twist are two main factors which may cause these departures.