We investigate the reflection of magnetosonic (MS) waves at the local two-ion cutoff frequency in the outer plasmasphere, which is rarely reported. The observed wave signals demonstrate the reflection at the local two-ion cutoff frequency. From simulations, the waves with small incident angles are more likely to penetrate the thin layer where the group velocity reduces significantly before reflection. These results may help to predict the global distribution of MS waves.

In this paper we show that the large thunderstorm called the "Great White Spot", which raged for about 9 months in Saturn's troposphere in 2010/2011, was accompanied by changes in the periodicity and phasing of auroral radio emissions. We suggest that the thunderstorm was a source of intense gravity waves causing a global change in Saturn’s ionospheric winds via energy and momentum deposition. This supports the theory that Saturn’s magnetospheric periodicities are driven by the upper atmosphere.