scholarly journals The Role of Localized Compressional Ultra-low Frequency Waves in Energetic Electron Precipitation

2018 ◽  
Author(s):  
I. Jonathan Rae ◽  
Kyle R. Murphy ◽  
Clare E. J. Watt ◽  
Alexa J. Halford ◽  
Ian R. Mann ◽  
...  
Keyword(s):  
Energetic Electron ◽  
Low Frequency ◽  
Electron Precipitation ◽  
Low Frequency Waves

Possible role of electromagnetic low frequency waves in the Io torus in the production of Jovian aurorae

1997 ◽  
Vol 45 (4) ◽  
pp. 483-493 ◽  
Author(s):  
L. Rezeau ◽  
N. Cornilleau-Wehrlin ◽  
G. Belmont ◽  
P. Canu ◽  
R. Prangé ◽  
...  
Keyword(s):  
Low Frequency ◽  
Low Frequency Waves

Statistical Distribution of Bifurcation of Earth's Inner Energetic Electron Belt at tens of keV

2021 ◽  
Author(s):  
Man Hua ◽  
Binbin Ni ◽  
Wen Li ◽  
Qianli Ma ◽  
Xudong Gu ◽  
...  
Keyword(s):  
Electron Energy ◽  
Energetic Electron ◽  
Low Frequency ◽  
Inner Magnetosphere ◽  
Near Earth Space ◽  
Naturally Occurring ◽  
Van Allen Probes ◽  
Radial Structure ◽  
Hemisphere Winter

<p>The Earth’s inner energetic electron belt typically exhibits one-peak radial structure with high flux intensities at radial distances < ~2.5 Earth radii. Recent studies suggested that human-made very-low-frequency (VLF) transmitters leaked into the inner magnetosphere can efficiently scatter energetic electrons, bifurcating the inner electron belt. In this study, we use 6-year electron flux data from Van Allen Probes to comprehensively analyze the statistical distributions of the bifurcated inner electron belt and their dependence on electron energy, season, and geomagnetic activity, which is crucial to understand when and where VLF transmitters can efficiently scatter electrons in addition to other naturally occurring waves. We reveal that bifurcation can be frequently observed for tens of keV electrons under relatively quiet geomagnetic conditions, typically after significant flux enhancements that elevate fluxes at L = 2.0 – ~2.5 providing the prerequisite for the bifurcation. The bifurcation typically lasts for a few days until interrupted by substorm injections or inward radial diffusion. The L-shells of bifurcation dip decrease with increasing electron energy, and the occurrence of bifurcation is higher during northern hemisphere winter than summer, supporting the important role of VLF transmitter waves in energetic electron loss in near-Earth space.</p>

The role of EEP forcing and background dynamics on the seasonal NO variability in the MLT region

2020 ◽  
Author(s):  
Christine Smith-Johnsen ◽  
Hilde Nesse Tyssøy ◽  
Daniel Marsh ◽  
Anne Smith
Keyword(s):  
Climate Model ◽  
Energetic Electron ◽  
Eddy Diffusion ◽  
Electron Precipitation ◽  
Ion Chemistry ◽  
D Region ◽  
E Region ◽  
Cluster Ion ◽  
Mlt Region

<p><a name="docs-internal-guid-803d1a38-7fff-fefe-52f7-d0a055a4547b"></a><a name="docs-internal-guid-b8d76d48-7fff-149a-6440-413c0de833ae"></a> <span>Energetic electron precipitation (EEP) ionizes the Earth's atmosphere and leads to production of nitric oxide (NO) from 50 to 150 km altitude. In this study we investigate the direct and indirect NO response to EEP using the Whole Atmosphere Community Climate Model (WACCM). In comparison to observations from SOFIE / AIM (Solar Occultation For Ice Experiment / Aeronomy of Ice in the Mesosphere), we find that EEP production of NO in the D-region is well simulated when both medium energy electron precipitation and negative and cluster ion chemistry is included in the model. However, the main EEP production of NO occurs in the E-region, and there the observed and modeled production differ. This discrepancy impacts also the D-region, and is seasonally dependent with the highest underestimate of D-region NO occuring during winter. The modeled transport across the mesopause during winter is generally weak, but strengthens with increased gravity wave activity. Increased eddy diffusion, increases NO at all altitudes through the polar MLT region</span></p>

scholarly journals On the propagation of MHD eigenmodes in a 2-D-magnetotail

2011 ◽  
Vol 29 (1) ◽  
pp. 19-30 ◽  
Author(s):  
G. Fruit ◽  
P. Louarn
Keyword(s):  
Plasma Sheet ◽  
Initial Perturbation ◽  
Low Frequency ◽  
Mhd Equations ◽  
General Idea ◽  
Gradient Term ◽  
Energy Flows ◽  
Set Up ◽  
Low Frequency Waves

Abstract. The propagation of MHD kink/sausage low frequency waves in the magnetotail with a finite normal Bz component is addressed. The general idea is to investigate how a finite Bz may affect the propagation of MHD eigenmodes in the plasma sheet. The standard MHD equations are linearized and solved numerically in a modified Harris sheet. Boundary conditions are chosen such that energy flows outward of the frame box (free propagating system). An initial perturbation is set up in the pressure gradient term and the wave energy is then traced in the system. While a pure 1-D-Harris sheet constitutes an efficient wave guide for MHD eigenmodes, the introduction of a finite Bz in the zero-order geometry changes significantly the propagation of MHD fluctuations: the eigenmodes propagate much more slowly and carry little energy whereas a pure sound wave is excited and propagates isotropically in the system. The presence of a finite Bz thus tends to inhibit the MHD propagation of energy along the plasma sheet. It tends rather to spread the energy throughout the magnetotail. As an application of the above study, the role of a permanent X-point structure on MHD propagation in the plasma sheet is also explored.

The interaction of high-frequency and low-frequency waves in magnetized plasmas

1988 ◽  
Vol 39 (3) ◽  
pp. 369-384 ◽  
Author(s):  
I. V. Relke ◽  
A. M. Rubenchik
Keyword(s):  
High Frequency ◽  
Low Frequency ◽  
Magnetized Plasmas ◽  
Magnetic Field Fluctuation ◽  
Hamiltonian Description ◽  
Frequency Wave ◽  
Magnetohydrodynamic Waves ◽  
Self Focusing ◽  
Low Frequency Waves

The interaction of high-frequency and low-frequency waves in magnetized plasmas is considered. The narrowness of high-frequency wave packets makes possible a concise Hamiltonian description of the problem. Some concrete problems are studied with the help of the derived equations. The competitive role of scattering in self-consistent density and magnetic-field fluctuation are considered. The self-focusing and solitons of potential plasma waves and magnetohydrodynamic waves are studied.

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