  We report the observation of non-stationary Quasi-Periodic Pulsations (QPPs)
in high-energy particles during the impulsive phase of an X4.8 flare on 2002
July 23 (SOL2002-07-23T00:35). The X4.8 flare was simultaneously measured by
the Reuven Ramaty High Energy Solar Spectroscopic Imager, Nobeyama Radio
Polarimeters, and Nobeyama Radioheliograph. The quasi-period of about 50 s,
determined by the wavelet transform, is detected in the Gamma-ray line
emission. Using the same method, a quasi-period of about 90 s is found in
Gamma-ray continuum, hard X-ray (HXR) and radio emissions during almost the
same time. Our observations suggest that the flare QPPs should be associated
with energetic ions and nonthermal electrons that quasi-periodically
accelerated by the repetitive magnetic reconnection. The different
quasi-periods between Gamma-ray line and continuum/HXR/radio emissions indicate
an apparent difference in acceleration or propagation between energetic ions
and nonthermal electrons of this solar flare.
