  Ultra-low-frequency (ULF) oscillations of the magnetospheric cusps are
observed permanently in the near-mid sector of auroral oval in the form of
so-called IPCL. In this paper, we posed the question: do electromagnetic waves
incident on cusp from the foreshock (it is a special region of cosmic plasma
existing before the front of the magnetosphere) affect the IPCL regime? We have
proposed a method of experimental investigation, which is based on the idea of
the foreshock position dependence on the interplanetary magnetic field (IMF)
orientation. A hypothesis has been put forward on the existence of a specific
effect of the IPCL north-south asymmetry. We tested our hypothesis using IPCL
observation data from the Hornsund (Spitsbergen) and Davis (Antarctica)
observatories. We found confirmation of the hypothesis at a high confidence
level of statistical significance. Keywords: magnetosphere, ultra-low-frequency
oscillations, north-south asymmetry.
