second harmonic

Takahashi, K., Oimatsu, S., e, M., Min, K., Claudepierre, S., Chan, A., et al. (2018). Van Allen Probes Observations of Second Harmonic Poloidal Standing Alfv\ en Waves. Journal Of Geophysical Research: Space Physics. http://doi.org/10.1002/2017JA024869 (Original work published January 2018)