  Using long-term X-ray observations, we present the short-term and long-term
X-ray variability analysis of the ultra-fast rotating active star AB Dor.
Flaring events are common in X-ray observations of AB Dor and occupy a
substantial portion of the total observation time, averaging around
57$\pm$23\%. The flare-free X-ray light curves show rotational modulation,
indicating the presence of highly active regions in its corona. We have
developed a light curve inversion code to image the corona of active fast
rotating stars. The results of coronal imaging reveal the presence of two
active regions of different brightness that are separated by $\sim$180\deg in
longitude. These active regions are also found to migrate along the longitude
and also show variation in their brightness. Our analysis of long-term X-ray
data spanning from 1979 to 2022 shows multiple periodicities. The existence of
a $\sim$19.2 yr cycle and its first harmonic indicates the presence of a
Solar-like, long-term pattern. In comparison, the periodicities of $\sim$3.6
and $\sim$5.4 yr are possibly due to the presence of a flip-flop cycle in
X-rays, which is also supported by similar periods findings from the optical
data in the earlier studies. Further confirmation of the existence of the X-ray
flip-flop cycle requires long-term observations at regular intervals in the
quiescent state.
