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Manninen, J., Kleimenova, N., Kozlovsky, A., Fedorenko, Y., Gromova, L., & Turunen, T. ( 2020). Ground‐based auroral hiss recorded in Northern Finland with reference to magnetic substorms. Geophysical Research Letters, 47, e2019GL086285. https://doi.org/10.1029/2019GL086285

Ground‐based auroral hiss Recorded in Northern Finland with reference to magnetic substorms

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Author: Manninen, Jyrki1; Kleimenova, Natalia2,3; Kozlovsky, Alexander1;
Organizations: 1Sodankylä Geophysical Observatory, Sodankylä, Finland
2Schmidt Institute of Physics of the Earth RAN, Moscow, Russia
3Space Research Institute RAN, Moscow, Russia
4Polar Geophysical Institute, Apatity, Russia
5Pushkov Institute of Terrestrial Magnetism, Ionosphere and Radio Wave Propagation RAN, Moscow, Russia
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 31.7 MB)
Persistent link: http://urn.fi/urn:nbn:fi-fe2020040110033
Language: English
Published: American Geophysical Union, 2020
Publish Date: 2020-04-01
Description:

Abstract

Very low frequency (VLF) auroral hiss at Kannuslehto (KAN), Finland, was analyzed with reference to the progress of 98 isolated magnetic substorms measured during the winter months of 2015–2018. Of these, 91 were accompanied by auroral hiss during the substorm growth phase. No auroral hiss was recorded during the expansion and recovery phases. We found that auroral hiss was observed under rising polar cap (PC) index, showing an increased solar wind energy input into the magnetosphere during the substorm growth phase. We also found that in 58 of the 65 events studied, KAN was located in the vicinity of enhanced field‐aligned currents (FACs) during auroral hiss occurrence. For the first time, it was established that auroral VLF hiss generation in the equatorial part of the auroral oval is a typical signature of a substorm growth phase.

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Plain Language Summary

Auroral hiss is a well‐known type of nighttime natural VLF emission with a noise‐like structure generated by the Cherenkov instability of precipitating soft electrons above the ionosphere. Auroral hiss occurrence up to 39 kHz was studied in the equatorward region of the auroral oval at the Finnish station Kannuslehto (KAN, MLAT = 64.2°N) during 11 winter months in 2015–2018. During this time interval, 98 isolated and rather powerful magnetic substorms were recorded over Scandinavia. In 93% of the substorms studied, an auroral VLF hiss was recorded at the same time as enhancement of field‐aligned currents (FACs). FACs are caused by soft electron precipitation which could be a plausible source of the auroral VLF hiss generation. For the first time, it was found that auroral VLF hiss occurrence in the equatorward region of the auroral oval is a typical signature of the substorm growth phase.

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Series: Geophysical research letters
ISSN: 0094-8276
ISSN-E: 1944-8007
ISSN-L: 0094-8276
Volume: 47
Issue: 6
Article number: e2019GL086285
DOI: 10.1029/2019GL086285
OADOI: https://oadoi.org/10.1029/2019GL086285
Type of Publication: A1 Journal article – refereed
Field of Science: 115 Astronomy and space science
Subjects:
Funding: The work of N.K., L.G., and Y.F. was partially supported by the grants of Academy of Finland (for N.K. and L.G. 308501 and 294931 for Y.F.).
Academy of Finland Grant Number: 308501
294931
Detailed Information: 308501 (Academy of Finland Funding decision)
294931 (Academy of Finland Funding decision)
Copyright information: © 2020. The Authors. This is an open access article under the terms of the Creative Commons Attribution‐NonCommercial‐NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non‐commercial and no modifications or adaptations are made.
  https://creativecommons.org/licenses/by-nc-nd/4.0/