We report observations of the ion dynamics inside an Alfven branch wave that propagates near the reconnecting dayside magnetopause. The measured frequency, wave normal angle and polarization are within 1% with the predictions of a dispersion solver, and indicate that the wave is an electromagnetic ion cyclotron wave with very oblique wave vector. The magnetospheric plasma contains hot protons (keV), cold protons (eV), plus some heavy ions. The cold protons follow the magnetic field fluctuations and remain frozen-in, while the hot protons are at the limit of magnetization. The cold proton velocity fluctuations contribute to balance the Hall term in Ohm’s law, allowing the wave polarization to be highly-elliptical and right-handed, a necessary condition for propagation at oblique wave normal angles. The dispersion solver indicates that increasing the cold proton density facilitates generation and propagation of these waves at oblique angles, as it occurs for the observed wave.

We present a study of the Schumann Resonance (SR) regular variations (March 2013-February 2017) using the ground-based magnetometers from the Sierra Nevada station, Spain (37◦02’N, 3◦19’W). The study is based on the fitting parameters obtained by the Lorentzian fit, calculated for each 10-min interval record, namely, peak amplitudes, central frequencies, width of the resonances and the power spectrum integral for the first 3 SR modes. We consider three time-scales in the study: seasonal, monthly and daily variations. The processed data collected by the Sierra Nevada station are also made public with this work. The general characteristics of the long-term evolution of the Schumann resonance are confirmed, but discrepancies appear that require further study comparing recent measurements from different stations. Signatures of the influences of the El Niño phenomenon and the solar cycle to SR have been found.