University of Oulu

Titova, E.E., Shklyar, D.R. & Manninen, J. Broadband Whistler Waves and Differential Electron Fluxes in the Equatorial Region of the Magnetosphere behind the Plasmapause during Substorm Injections. Geomagn. Aeron. 62, 399–412 (2022).

Broadband whistler waves and differential electron fluxes in the equatorial region of the magnetosphere behind the plasmapause during substorm injections

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Author: Titova, E. E.1,2; Shklyar, D. R.2; Manninen, J.3
Organizations: 1Polar Geophysical Institute, Russian Academy of Sciences, Apatity, Murmansk oblast, Russia
2Space Research Institute, Russian Academy of Sciences, Moscow, Russia
3Sodankylä Geophysical Observatory, Sodankylä, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 1.5 MB)
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Language: English
Published: Pleiades Publishing, 2022
Publish Date: 2023-06-29


This paper considers the whistler waves in the frequency band from 3 to 30 kHz observed on the Van Allen Probe-B satellite on March 17, 2019, when the satellite was on L-shells from 2.8 to 5.4. The upper frequency in the emission spectrum followed the course of the electron gyrofrequency fce and was lower than it by 1–5 kHz. The emission spectrum often had two spectral maxima (above and below fce/2); the maximum at frequencies above fce/2 could be either more or less intense. High-frequency whistler waves at frequencies > fce/2 were observed simultaneously with an increase in low-energy electron fluxes with energies more than 102 eV, which had transverse anisotropy. To explain the observed spectrum, we used simultaneous satellite measurements of the cold plasma density and differential fluxes of energetic electrons in the energy range from 0.015 to 250 keV in a wide range of pitch angles to determine the electron distribution function and calculate local linear growth rate as a function of frequency f and wave normal angle θ. The calculations were performed for three cyclotron resonances (n = 1, 0, –1) that make the largest contributions to the wave growth rate. The calculations showed the presence of a pronounced maximum at frequencies (0.8–0.9) fce. The energy range and pitch angles of electrons with a maximum contribution to wave excitation at these frequencies were estimated.

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Series: Geomagnetism and aeronomy
ISSN: 0016-7932
ISSN-E: 1555-645X
ISSN-L: 0016-7932
Volume: 62
Issue: 4
Pages: 399 - 412
DOI: 10.1134/s0016793222040168
Type of Publication: A1 Journal article – refereed
Field of Science: 115 Astronomy and space science
Funding: The work by E. Titova and D. Shklyar on the analysis of Van Allen Probes data and the calculations of the growth rate of whistler waves was supported by the Russian Science Foundation, project no. 22-22-00135. The processing of ground-based observation data was supported by the Finland Academy of Sciences, project no. 330 783.
Academy of Finland Grant Number: 330783
Detailed Information: 330783 (Academy of Finland Funding decision)
Copyright information: © The Author(s), 2022. 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 license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license 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 license, visit