  Quasi-periodic fast-propagating (QFP) magnetosonic wave trains are commonly
observed in the low corona at extreme ultraviolet wavelength bands. Here, we
report the first white-light imaging observation of a QFP wave train
propagating outwardly in the outer corona ranging from 2 to 4 solar Radii. The
wave train was recorded by the Large Angle Spectroscopic Coronagraph on board
the Solar and Heliospheric Observatory, and it was associated with a GOES M1.5
flare in NOAA active region AR12172 at the southwest limb of the solar disk.
Measurements show that the speed and period of the wave train were about 218
km/s and 26 minutes, respectively. The extreme ultraviolet imaging observations
taken by the Atmospheric Imaging Assembly on board the Solar Dynamic
Observatory reveals that in the low corona the QFP wave train was associated
with the failed eruption of a breakout magnetic system consisting of three
low-lying closed loop systems enclosed by a high-lying large-scale one. Data
analysis results show that the failed eruption of the breakout magnetic system
was mainly because of the magnetic reconnection occurred between the two sided
low-lying closed-loop systems. This reconnection enhances the confinement
capacity of the magnetic breakout system because the upward-moving reconnected
loops continuously feed new magnetic fluxes to the high-lying large-scale loop
system. For the generation of the QFP wave train, we propose that it could be
excited by the intermittent energy pulses released by the quasi-periodic
generation, rapid stretching and expansion of the upward-moving, strongly bent
reconnected loops.
