EDP Sciences
Free access
Issue
A&A
Volume 393, Number 2, October II 2002
Page(s) 649 - 659
Section The Sun
DOI http://dx.doi.org/10.1051/0004-6361:20021057


A&A 393, 649-659 (2002)
DOI: 10.1051/0004-6361:20021057

A wavelet analysis of quasi-periodic variability across a solar coronal hole region

M. S. Marsh, R. W. Walsh and B. J. I. Bromage

Centre for Astrophysics, University of Central Lancashire, Preston, PR1 2HE, UK

(Received 3 May 2002 / Accepted 18 July 2002)

Abstract
High time resolution ( $\approx$13 s cadence) Solar and Heliospheric 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 $\log T_{\rm e}=$ 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 s and 1500 s. Observations of short wavepackets with periods of the order 50-100 s with durations of 2-5 cycles are reported. Observations of a decay in the driving period over time are also described.


Key words: Sun: corona -- Sun: oscillations -- Sun: transition region -- Sun: UV radiation -- waves

Offprint request: M. S. Marsh, mmarsh@uclan.ac.uk




© ESO 2002