Giant macro-spicule as observed by CDS on SOHO

Citation
D. Banerjee et al., Giant macro-spicule as observed by CDS on SOHO, ASTRON ASTR, 355(3), 2000, pp. 1152-1159
Citations number
26
Categorie Soggetti
Space Sciences
Journal title
ASTRONOMY AND ASTROPHYSICS
ISSN journal
00046361 → ACNP
Volume
355
Issue
3
Year of publication
2000
Pages
1152 - 1159
Database
ISI
SICI code
0004-6361(200003)355:3<1152:GMAOBC>2.0.ZU;2-O
Abstract
We examine spectral time series of coronal line Mg Ix 368 Angstrom and tran sition region line O v 629 A, observed with the Coronal Diagnostic Spectrom eter (CDS) onboard the SOHO spacecraft. Primarily we were looking for inten sity and velocity oscillations in polar plumes, however by chance we detect ed a giant macro-spicule at the limb and were able to follow its dynamical structure. Blue and red-shifted emission in the O v line indicates that it is probably a rotating twisted magnetic jet. Emission is also detected in t he Mg Ix 368 Angstrom line, at a temperature of 1 million K. Both Fourier and wavelet transforms have been applied independently to the analysis of the oscillations in order to find the most reliable periods. We report here on the existence of long period oscillations in the polar plum es as observed in the O v 629 Angstrom line. Our observations indicate the presence of compressional waves with periods of 20-25 minutes.