  Coronal mass ejections (CMEs) are energetic expulsions of organized magnetic
features from the Sun. The study of CME quasi-periodicity helps establish a
possible relationship between CMEs, solar flares, and geomagnetic disturbances.
We used the angular width of CMEs as a criterion for classifying the CMEs in
the study. Based on 25 years of observational data, we systematically analyzed
the quasi-periodic variations corresponding to the CME occurrence rate of
different angular widths in the northern and southern hemispheres, using
frequency and time-frequency analysis methods. There are various periods for
CMEs of different angular widths: 9 months, 1.7 years, and 3.3-4.3 years.
Compared with previous studies based on the occurrence rate of CMEs, we
obtained the same periods of 1.2(+-0.01) months, 3.1(+-0.04) months,
~6.1(+-0.4) months, 1.2(+-0.1) years, and 2.4(+-0.4) years. We also found
additional periods of all CMEs that appear only in one hemisphere or during a
specific solar cycle. For example, 7.1(+-0.2) months and 4.1(+-0.2) years in
the northern hemisphere, 1(+-0.004) months, 5.9(+-0.2) months, 1(+-0.1) years,
1.4(+-0.1) years, and 2.4(+-0.4) years in the southern hemisphere, 6.1(+-0.4)
months in solar cycle 23 (SC23) and 6.1(+-0.4) months, 1.2(+-0.1) years, and
3.7(+-0.2) years in solar cycle 24 (SC24). The analysis shows that
quasi-periodic variations of the CMEs are a link among oscillations in coronal
magnetic activity, solar flare eruptions, and interplanetary space.
