Speaker: Clare Watt [Northumbria University]
Topic: Occurrence Rates and Variability of Whistler-Mode Waves in the Plasma Trough
Date & Time: 7 January 2026 @ 17:00 UTC | 8:00 PST | 11:00 EST | 18:00 CET
Speaker intro and paper abstract:
As part of a large team, I recently published a paper on whistler-mode waves in Earth’s inner magnetosphere. I’d like to present the work in the context of the research project that funded the work, ongoing collaborations and history of some of the ideas that went into the paper.
Numerical models of energetic electron behaviour in the outer radiation belt require descriptions of the wave-particle interactions across the inner magnetosphere. Quasilinear diffusion coefficients describe gyro-resonant wave-particle interactions over large time- and length-scales but these must be constrained by observations to construct realistic radiation belt models. Recent work indicates the importance of identifying and including realistic spatiotemporal variation of diffusion coefficients. In this paper, we study the spatiotemporal variability of whistler-mode waves outside the plasmasphere, typically referred to as whistler-mode chorus. We separately consider the probability of (a) parts of the model domain being outside the plasmasphere, and (b) the probability of detecting wave activity should that part of the model domain be outside the plasmasphere. We discover that the spatiotemporal variability of whistler-mode waves significantly differs across the model domain; we propose that wave power variability in short wave intervals (5 min) is a useful characteristic to distinguish between two types of whistler-mode waves, especially where their frequency ranges overlap. Our novel spatiotemporal variability analysis indicates that low variability waves are dayside exohiss whose typically high occurrence rate (~0.8) decreases with substorm activity, and high variability waves are sporadic post-midnight/dawn sector substorm-driven chorus with a typical occurrence rate of 0.2. Further, although previous studies often combine the occurrence rates and wave characteristics into climatological averages of chorus wave power, this study highlights the importance of separating the study of occurrence rates and power of the waves, since each can have a different relationship with driving factors.
Rachel Black | Ph.D. student @ British Antarctic Survey (since 2023)
Miroslav Hanzelka | Researcher @ IAP CAS Prague (since 2020)
Jodie McLennan | Ph.D. Student @ University of Iowa (since 2025)
Yang Mei | Ph.D. Student @ University of Colorado Boulder (since 2025)
Harriet George | Postdoctoral Researcher @ IRF Uppsala (since 2025)
Suhail Aldhurais | Ph.D. Student @ Rice University (since 2025)
Claudia Martinez, co-founder & organizer (2018 - 2023)
Lilla Juhász, organizer (2020 - 2021)
Liliana Macotela, co-founder & organizer (2018 - 2020)
During the 8th VERSIM workshop in 2018, we had several opportunities to discuss science and the future of our group. One of the ideas put forward was the creation of a Journal Club, in which we could discuss a published paper of interest to the VERSIM community. In particular, we hope to encourage scientific discussion between students and scientists.
In 2025, we joined forces with the GEM (Geospace Environment Modeling) focus group RBSoS (Radiation Belts as a System of Systems) to bring in more organizers and to broaden our audience.
From 2026, we plan to have monthly online seminars, always on the first Wednesday of the month. Speakers are invited by the organizers, maintaining a good balance between student, ECR, and senior speakers. Presentations focus either on a single published paper or an active research topic, and are followed by an extended discussion. Our goal is to create a friendly and lively environment where students can learn and engage, and build their scientific confidence.
Although the original purpose was to foster connections between students in the VERSIM and GEM community, we also want to promote interaction across generations of scientists, so everyone is welcome! If you like discussing science, sharing your knowledge, and motivating your juniors, we would like to hear from you.
To join the Journal Club, request subscription to the mailing list, or submit any related inquiries, please message the organizers: versim.jc*'at'*gmail.com.
Studies on lightning-induced electron precipitation using DEMETER satellite [V. Linzmayer]
Observations of Electromagnetic Waves by the DEMETER Spacecraft and the Kannuslehto Station [K. Drastichová]
Ring Current Electron Precipitation During the 17 March 2013 Geomagnetic Storm [A. Grishina]
The importance of diffuse-like aurora and mesoscale precipitation.
Sub-MeV EMIC-driven Electron loss - The 'impossible' effect? [A. Hendry]
Effect of ground conductivity on VLF propagation in the Earth-ionosphere waveguide [P. Teysseyre]
Three-Dimensional Simulations of Ultra-Relativistic Electron Acceleration During the 21 April 2017 Storm [Guo et al., 2023]
Formation of Banded Chorus Waves by Propagation From Multiple Sources [Tao et al., 2023]
Opening the Black Box of the Radiation Belt Machine Learning Model [Ma et al., 2023]
Nonresonant Scattering of Relativistic Electrons by Electromagnetic Ion Cyclotron Waves in Earth's Radiation Belts [An et al., 2022]
Solar effects on the Global Electric Circuit [J. Tacza]
Seed population of relativistic energy electrons in outer radiation belt observed by ARASE satellite [I. Park]
Watching for Solar Tsunami: Adventures in Installing a Variometer Network [A. Hendry]
Can ULF waves be observed without substorms? [A. Rubtsov]
Properties of Lightning Generated Whistlers Based on Van Allen Probes Observations and Their Global Effects on Radiation Belt Electron Loss [Green et al. 2020]
Observations and simulations of wave propagation properties of equatorial noise observed at low altitudes [M. Hanzelka]
EMIC waves: Rising and falling tones - Can they be together? [B. Ojha]
The Applicability of the Lowest Part of the ELF Range (<100 Hz) for Remote Sensing the Atmosphere-Ionosphere-Magnetosphere System. [T. Bozoki]
Multi-wavelength imaging observations of STEVE at Athabasca, Canada [Yadav et al., 2021]
Multiple time-scale beats in aurora: precise orchestration via magnetospheric chorus waves [Hosokawa et al., 2021]
Magnetospheric connections to the atmosphere [Andersson et al., 2014]
ELF/VLF Ground Observations: Challenges and Opportunities [Golkowski et al., 2008; 2018]
The Source Region of Whistlers [D. Koronczay et al., 2019]
Statistics of Geomagnetic Perturbations and Space Weather Implications [K. Reiter]
Source region analysis and Spatiotemporal extension of the EMIC subpackets [B. Ojha]
Effect of the interaction between chorus waves and electrons on the hot electron distribution function: A test particle study [Hanzelka+2020]
Dependence of Properties of Magnetospheric Line Radiation and Quasiperiodic Emissions on Solar Wind Parameters and Geomagnetic Activity [Bezdekova et al., 2019]
Comparison of Electron Loss Models in the Inner Magnetosphere During the 2013 St. Patrick's Day Geomagnetic Storm [Ferradas et al., 2019]
A computational and theoretical investigation of nonlinear wave-particle interactions in oblique whistlers [Nunn and Omura, 2015]
What Fraction of the Outer Radiation Belt Relativistic Electron Flux at L=3-4.5 Was Lost to the Atmosphere During the Dropout Event of the St. Patrick's Day Storm of 2015? [Gokani et al., 2019]
A Systematic Study in Characteristics of Lower Band Rising Tone Chorus Elements [Shue et al., 2019]
Fine structure of large-amplitude chorus wave packets [Santolik et al., 2013]
Unusual Electromagnetic Signatures of European North Atlantic Winter Thunderstorms [Santolik and Kolmasova, 2017]
Seasonal dependence of energetic electron precipitation: Evidence for a global role of lightning [Gemelos et al., 2009]
Properties of unipolar magnetic field pulse trains generated by lightning discharges. [Kolmasova and Santolik, 2013]
Contrasting the responses of three different ground-based instruments to energetic electron precipitation.[Rodger et al., 2012]
Relationship Between the Parameters of the Linear and Nonlinear Wave Generation Stages in a Magnetospheric Cyclotron Maser in the Backward-Wave Oscillator Regime. [Demekhov, 2017]
Lower Ionospheric Plasma-Chemical Evolution and VLF Signal Modulation by a Series of SGR X-Ray Bursts: Numerical SimulationWith an Ion-Chemistry Model. [Palit, Raulin, and Correia, 2018]
Remote Sensing of Radiation Belt Energetic Electrons Using Lightning Triggered Upper Band Chorus. [Hosseini, Golkowski, and Harid, 2019]
The role of density depletion and meter-scale irregularities in the observation of auroral hiss: ground observation. [Sonwalkar and Harikumar, 2000]
Longitudinal Dependence of Whistler Mode Electromagnetic Waves in the Earth's Inner Magnetosphere [Zahlava et al., 2018]
Non-linear wave generation special discussion (part 2) : Introduction to chorus generation (tools and simulation, non-linear approach) and special Q&A session with Prof. Yuto Katoh.
Introduction to non linear wave generation processes. Generation Processes of Whistler Mode Chorus Emissions: Current Status of Nonlinear Wave Growth Theory [Omura et al., 2012]
Ground-based observations at L=6 of multi-band structures in VLF hiss [Titova et al., 2007]
Simulation of VLF chorus emissions in the magnetosphere and comparison with THEMIS spacecraft data [Demekhov et al., 2016]
A statistical study over Europe of the relative locations of lightning and associated energetic burst of electrons from the radiation belt [Burriez et al., 2016]
The lower ionospheric VLF/LF response to the 2017 great American solar eclipse observed across the continent [Cohen et al., 2018]
Synthetic empirical chorus wave model from combined Van Allen Probes and Cluster statistics [Agapitov et al., 2018]
Identification of the source of quasiperiodic VLF emissions using ground-based and Van Allen Probes satellite observations [Titova et al., 2015]
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