Horvath and Lovell  are the first to describe two separate geomagnetic storm events occurring in 2017 in which detected Kelvin-Helmholtz (K-H) waves on the magnetopause were observed to be correlated with surface waves in the hot zone of the outer plasmasphere. The Near-Earth Plasma Sheet (NEPS), activated by the K-H waves, acts as a resonator with eigenfrequencies in the Pc4-5 range, and leads to surface waves in the low-density hot zone of the outer plasmasphere.
Observations confirm the coupling along magnetic field lines through field-aligned currents that link these high-altitude undulations to the auroral region. For one event a complex flow channel structure in the auroral regions was observed that appeared as sub-auroral ion drifts (SAIDs) early in the storm, and as sub-auroral polarization streams (SAPS) and abnormal SAIDs at later times. Observed wave structure embedded within the SAPS appeared to correlate well with the KH waves. The paper demonstrates the complex coupling that occurs over extremely large distances from the magnetopause to the auroral zones.
Citation: Horvath, I., & Lovell, B. C. . Subauroral flow channel structures and auroral undulations triggered by Kelvin-Helmholtz waves. Journal of Geophysical Research: Space Physics, 126, e2021JA029144. https://doi.org/10.1029/2021JA029144
—Michael P. Hickey, Editor, JGR: Space Physics