University of Oulu

Martinez-Calderon, C., Manninen, J.K., Manninen, J.T. et al. A review of unusual VLF bursty-patches observed in Northern Finland for Earth, Planets and Space. Earth Planets Space 73, 191 (2021). https://doi.org/10.1186/s40623-021-01516-y

A review of unusual VLF bursty-patches observed in Northern Finland for Earth, Planets and Space

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Author: Martinez‑Calderon, Claudia1; Manninen, Jyrki K.2; Manninen, Jemina T.2;
Organizations: 1Institute for Space-Earth Environmental Research, Nagoya, Japan
2Sodankylä Geophysical Observatory, Sodankylä, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 5.2 MB)
Persistent link: http://urn.fi/urn:nbn:fi-fe2021102552130
Language: English
Published: Springer Nature, 2021
Publish Date: 2021-10-25
Description:

Abstract

Using numerical filtering techniques allowing us to reduce noise from sferics, we are able to clearly study a new type of differently structured very low frequency (VLF) radio waves above f = 4 kHz at the ground station of Kannuslehto in northern Finland (KAN, MLAT = 64.4°N, L = 5.5). These emissions are intriguing, since they are detected at frequencies above half the electron gyrofrequency in the equatorial plane (fce) for the L-shell of Kannuslehto (fce ~ 5–6 kHz). They are commonly observed at Kannuslehto, but have also been infrequently reported at other stations, sometimes under different names. Their possible common origin and manner of propagation is still under investigation. This paper unifies the nomenclature by regrouping all these waves detected at frequencies higher than the local equatorial 0.5 fce at the L-shell of observation under the name of VLF bursty-patches. While these waves have different spectral features, they appeared mostly composed of hiss bursts with durations of a few seconds to several minutes. They also show periodic features with varying periodicity and shape. They are sometimes characterized by single bursts covering very large frequency ranges of several kHz. We also give a review of the different characteristics of VLF bursty-patches observed at Kannuslehto, which at the moment, is the station with the highest observation rate. We present recent observations between 2019 and 2021.

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Series: Earth, planets and space
ISSN: 1343-8832
ISSN-E: 1880-5981
ISSN-L: 1343-8832
Volume: 73
Article number: 191
DOI: 10.1186/s40623-021-01516-y
OADOI: https://oadoi.org/10.1186/s40623-021-01516-y
Type of Publication: A2 Review article in a scientific journal
Field of Science: 115 Astronomy and space science
Subjects:
Funding: The instrumentation and data analysis are entirely funded by the Sodankylä Geophysical Observatory and the University of Oulu. CMC benefited from an ArcI International Visiting Grants from the University of Oulu that funded travel to Finland to work with the data in-situ. CMC research and analysis is funded by Nagoya University and the PWING project (JSPS 16H06286).
Dataset Reference: All the VLF data from KAN is available as quick-plots at https://www.sgo.fi/pub_vlf/. Any additional data in other formats can be requested by contacting the PI of the instrument Jyrki Manninen.
  https://www.sgo.fi/pub_vlf/
Copyright information: © The Author(s) 2021. Open Access. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.
  https://creativecommons.org/licenses/by/4.0/