  On 2011 May 30, quasi-periodic fast propagating (QFP) magnetosonic waves
accompanied by a C2.8 flare were directly imaged by the Atomospheric Imaging
Assembly instrument on board the Solar Dynamics Observatory. The QFP waves
successively emanated from the flare kernel, they propagated along a cluster of
open coronal loops with a phase speed of 834 km/s during the flare's rising
phase, and the multiple arc-shaped wave trains can be fitted with a series of
concentric circles. We generate the k-omega diagram of the Fourier power and
find a straight ridge that represents the dispersion relation of the waves.
Along the ridge, we find a lot of prominent nodes which represent the available
frequencies of the QFP waves. On the other hand, the frequencies of the flare
are also obtained by analyzing the flare light curves using the wavelet
technique. The results indicate that almost all the main frequencies of the
flare are consistent with those of the QFP waves. This suggests that the flare
and the QFP waves were possibly excited by a common physical origin. On the
other hand, a few low frequencies revealed by the k-omega diagram can not be
found in the accompanying flare. We propose that these low frequencies were
possibly due to the leakage of the pressure-driven p-mode oscillations from the
photosphere into the low corona, which should be a noticeable mechanism for
driving the QFP waves observed in the corona.
