A wavelet analysis of active region oscillations

The wavelet transform is applied to the analysis of active region oscillati ons. The localised (in time) nature of the wavelet transform allows us to s tudy both the duration of any statistically significant oscillations as wel l as their period. Time series arising from SOHO (Solar and Heliospheric Ob servatory) CDS-NIS (Coronal Diagnostic Spectrometer Normal Incidence Spectr ometer) active region observations on 14th-15th November 1996 are used to d emonstrate the applicability of wavelet methods. High cadence (approximatel y 14 seconds) observations were made in He I 584.33 Angstrom (log T-e = 4.3 ), O V 629.73 Angstrom (log T-e = 5.3), Mg IX 368.06 Angstrom (log T-e = 6. 0), Fe XVI 360.76 Angstrom (log T-e = 6.4) provide detailed intensity infor mation on the active region over a wide range of temperatures. The distribu tion of statistically significant periods found varies from line to line, a s does their duration.