The IMF impact on the ULF oscillations in the magnetospheric polar cusps

TL;DR

This study investigates how the interplanetary magnetic field influences ultra-low-frequency oscillations in Earth's magnetospheric cusps, revealing a significant north-south asymmetry linked to IMF orientation.

Contribution

The paper introduces a novel experimental method to analyze IMF effects on ULF oscillations and confirms the existence of a north-south asymmetry in IPCL behavior.

Findings

Confirmed IMF influence on ULF oscillations

Identified a significant north-south asymmetry

Validated hypothesis with high statistical confidence

Abstract

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.