| Autor: |
Nykyri, K., Di Matteo, S., Archer, M. O., Ma, X., Hartinger, M. D., Sarantos, M., Zesta, E., Paterson, W. R. |
| Zdroj: |
Geophysical Research Letters; Nov2024, Vol. 51 Issue 22, p1-10, 10p |
| Abstrakt: |
Both ground based magnetometers and ionospheric radars at Earth have frequently detected Ultra Low Frequency (ULF) fluctuations at discrete frequencies extending below one mHz‐range. Many dayside solar wind drivers have been convincingly demonstrated as driver mechanisms. In this paper we investigate and propose an additional, nightside generation mechanism of a low frequency magnetic field fluctuation. We propose that the Moon may excite a magnetic field perturbation of the order of 1 nT at discrete frequencies when it travels through the Earth's magnetotail ≈ ${\approx} $4–5 days every month. Our theoretical prediction is supported by a case study of ARTEMIS magnetic field measurements at the lunar orbit in the Earth's magnetotail. ARTEMIS detects statistically significant peaks in magnetic field fluctuation power at frequencies of 0.37–0.47 mHz that are not present in the solar wind. Plain Language Summary: Throughout history, the Moon has both captivated the human mind as well as had important practical consequences on the lives of people in coastal areas. Humans have attributed the Full Moon to all types of things, many of which do not stand up to scientific scrutiny. Recent spacecraft measurements have shown that the Moon has significant magnetic anomalies that are strong enough for producing a magnetic cavity in the solar wind plasma. The Moon also has a wake structure with a strong electrostatic potential which may act as a perturbation for the magnetic field lines. Here, by using ARTEMIS spacecraft observations in the magnetotail, we found surprisingly that the Moon may weakly perturb the Earth's magnetosphere when it travels through the magnetotail in about 4–5 days around the time of the Full Moon. This effect may have been stronger in the past, when Moon was closer to the Earth and its magnetic field was stronger. Key Points: A hypothesis for the Earth's magnetic field perturbation caused by the Moon in the magnetotail is proposedMagnetometer onboard ARTEMIS spacecraft detects the fundamental frequency corresponding to this theoretical predictionThese initial findings suggest the need for followup space and ground‐based statistical studies of the Moon‐Earth field line resonator [ABSTRACT FROM AUTHOR] |
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