摘要：On 1996 December 19, the Ultraviolet Coronagraph Spectrometer (UVCS) on board the Solar
and Heliospheric Observatory (SOHO) conducted a special high-cadence sit-and-stare
observation in the O vi 1032 Å spectral line above a polar coronal hole at a
heliocentric distance of 1.38 R⊙. The ~ 9-h dataset was analyzed by applying
advanced spectral techniques to investigate the possible presence of propagating waves.
Highly significant oscillations in O vi intensity (P = 19.5 min) and Doppler
shift (P =
7.2 min) were detected over two different portions of the UVCS entrance
slit. A cross-correlation analysis between the O vi intensity and Doppler shift
fluctuations shows that the most powerful oscillations were in phase or anti-phase over
the same portions of the slit, thus providing a possible signature of propagating
magnetosonic waves. The episodic nature of the observed oscillations and the large
amplitudes of the Doppler shift fluctuations detected in our observations, if not
attributable to line-of-sight effects or inefficient damping, may indicate that the
observed fluctuations were produced by quasi-periodic upflows.
