  Mid-term quasi-periodicities in solar coronal mass ejections (CMEs) during
the most recent solar maximum cycle 23 are reported here for the first time
using the four-year data (February 5, 1999 to February 10, 2003) of the Large
Angle Spectrometric Coronagraph (LASCO) onboard the Solar and Heliospheric
Observatory (SOHO). In parallel, mid-term quasi-periodicities in solar X-ray
flares (class >M5.0) from the Geosynchronous Operational Environment Satellites
(GOES) and in daily averages of Ap index for geomagnetic disturbances from the
World Data Center (WDC) at the International Association for Geomagnetism and
Aeronomy (IAGA) are also examined for the same four-year time span. Several
conceptual aspects of possible equatorially trapped Rossby-type waves at and
beneath the solar photosphere are discussed.
