A WAVELET ANALYSIS OF QUASI-PERIODIC VARIABILITY WITHIN THE SOLAR CORONA

摘要

High time resolution (≈13 sec cadence) Solar and Helio-spheric Observatory (SOHO) Coronal Diagnostic Spectrometer (CDS) Grazing Incidence Spectrometer (GIS) time series data is analysed for evidence of quasi-periodic variability in the solar corona. The observations are obtained from a GIS study of a coronal hole boundary region taken in October 1997. A wavelet analysis is applied to EUV emission lines covering a temperature range of log T_e = 5.3-6.1 K. Wavelet analysis allows the frequency and temporal information of any periods present within the data to be analysed. Statistically significant periods are found within the range 100-900 seconds. Observations of short wavepackets with periods of the order 50-100 seconds with durations of 2-5 oscillations are reported.