Dear loop enthusiats,
Here are two papers recently published in ApJ that you might find of interest:
1. The first paper shows how to take into account the power-law nature of the power spectra of most solar intensity time-series in order to perform robust Fourier and wavelet analysis. It illustrates how data detending can lead to false positive detections. It also demonstrates that the white and red noise models built into the widely used wavelet code of Torrence & Compo cannot adequately represent the power spectra of coronal time series, thus also possibly causing false positives. It then gives practical details on how to use the Torrence & Compo code with custom pertinent noise models (including power-laws). Finally, we derive rigorous confidence levels taking account the total number of degrees of freedom in the wavelet spectra.
https://ui.adsabs.harvard.edu/#abs/2016ApJ...825..110A/abstract
2. We recently detected numerous pulsations of long-period (hours) in coronal loops (Auchère et al 2014 https://ui.adsabs.harvard.edu/#abs/2014A&A...563A...8A/abstract). Using Fourier and wavelet analysis, we demonstrate that the observed periodic signals are not signatures of vibrational modes. Instead, superimposed on the power law expected from the stochastic background emission, the power spectra of the time series exhibit the discrete harmonics and continua expected from periodic trains of pulses of random amplitudes. These characteristics reinforce our earlier interpretation of these pulsations as being cycles of evaporation / condensation.
https://ui.adsabs.harvard.edu/#abs/2016ApJ...827..152A/abstract
Best regards,
Frédéric Auchère