  Quasi-periodic, fast-mode, propagating wave trains (QFPs) are a new
observational phenomenon recently discovered in the solar corona by the Solar
Dynamics Observatory with extreme ultraviolet (EUV) imaging observations. They
originate from flares and propagate at speeds up to ~2000 km/s within
funnel-shaped waveguides in the wakes of coronal mass ejections (CMEs). QFPs
can carry sufficient energy fluxes required for coronal heating during their
occurrences. They can provide new diagnostics for the solar corona and their
associated flares. We present recent observations of QFPs focusing on their
spatio-temporal properties, temperature dependence, and statistical correlation
with flares and CMEs. Of particular interest is the 2010-Aug-01 C3.2 flare with
correlated QFPs and drifting zebra and fiber radio bursts, which might be
different manifestations of the same fast-mode wave trains. We also discuss the
potential roles of QFPs in accelerating and/or modulating the solar wind.
