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Quasilinear Analysis in the Source Region of Jovian Hectometric Emissions Associated with Upward Electron Beams
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Quasilinear Analysis in the Source Region of Jovian Hectometric Emissions Associated with Upward Electron Beams

Peter H. Yoon, J. Douglas Menietti, Frederic Allegrini, William S. Kurth, George Hospodarsky, Terrance Averkamp, Jeremy B. Faden, Jack E. P. Connerney and Scott J. Bolton
Zenodo
11/25/2024
DOI: 10.5281/zenodo.14218813
url
https://doi.org/10.5281/zenodo.14218813View
Open Access

Abstract

This is the supporting data set for the paper by the same title published in AGU JGR Space Physics. Key Points: Upward electron beams detected in HOM source region excite low-frequency waves. One-sided loss-cone electron distribution excites extraordinary mode via cyclotron maser instability, which leads to HOM emission. The Observed wave spectra and particle characteristics can be modeled by employing quasilinear wave-particle analysis. Plain Language Summary: NASA’s Juno space probe orbiting the planet Jupiter measured energetic electrons streaming out from the northern polar region of the planet. These electrons were seen to travel in an environment permeated by high-frequency radio emission called the Jovian hectometric emission. By employing a mathematical model known as the quasilinear plasma kinetic theory the essential characteristics of the electrons and the electromagnetic wave spectra measured by the Juno space probe are theoretically replicated. This exercise helps scientists understand the nature of physical processes taking place in the space environment surrounding the planet Jupiter. Abstract: Intense upward electron beams were measured by the Juno JADE instrument in the northern hemisphere, low-latitude auroral zone source region. In this study we report on how these electron beams interact with plasma near and within the Jovian hectometric (HOM) emission (1 MHz < f < 5 MHz) source region. Within the source region large upward loss cones are observed in the northern polar region at radial distances of ∼ 2Rj, magnetic latitude of ∼ 70◦ . Intense, narrow electron beams (E < 3 keV) are then observed, but within one second wave-particle scattering is observed, filling the loss cone to energies > 50 keV. These energies persist for several seconds before fading, leaving an empty loss cone again. The loss cone provides a free-energy source for HOM emission resulting from the cyclotron maser instability. We use quasilinear analysis to examine the generation of HOM and the dynamics of wave-particle interaction of the electron beams with HOM, and the generation via Landau interaction of whistler mode emission. The dynamic spectrum of the HOM emission generated by the loss-cone electrons as well as that of the low-frequency whistler-mode waves generated by the up-going electron beam can be constructed by quasilinear theory, which compare well with observation. The saturated state of the energetic electron velocity distribution function constructed via quasilinear theory also compare reasonably with observation.

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