Strong Diffusion of Energetic Electrons by Equatorial Chorus Waves in the Midnight‐to‐Dawn Sector

2019 ◽  
Vol 46 (22) ◽  
pp. 12685-12692 ◽  
Author(s):  
S. Kasahara ◽  
Y. Miyoshi ◽  
S. Kurita ◽  
S. Yokota ◽  
K. Keika ◽  
...  
Keyword(s):  
Energetic Electrons ◽  
Chorus Waves ◽  
Dawn Sector ◽  
Strong Diffusion

scholarly journals Electron Microbursts Induced by Nonducted Chorus Waves

2021 ◽  
Vol 8 ◽  
Author(s):  
Lunjin Chen ◽  
Xiao-Jia Zhang ◽  
Anton Artemyev ◽  
Liheng Zheng ◽  
Zhiyang Xia ◽  
...  
Keyword(s):  
Field Line ◽  
Particle Simulation ◽  
Electron Precipitation ◽  
Outer Radiation Belt ◽  
Energetic Electrons ◽  
Chorus Waves ◽  
Wave Normal ◽  
Intense Electron ◽  
The Magnetic Field ◽  
Normal Angle

Microbursts, short-lived but intense electron precipitation observed by low-Earth-orbiting satellites, may contribute significantly to the losses of energetic electrons in the outer radiation belt. Their origin is likely due to whistler mode chorus waves, as evidenced by a strong overlap in spatial correlation of the two. Despite previous efforts on modeling bursty electron precipitation induced by chorus waves, most, if not all, rely on the assumption that chorus waves are ducted along the field line with zero wave normal angle. Such ducting is limited to cases when fine-scale plasma density irregularities are present. In contrast, chorus waves propagate in a nonducted way in plasmas with smoothly varying density, allowing wave normals to gradually refract away from the magnetic field line. In this study, the interaction of ducted and nonducted chorus waves with energetic electrons is investigated using test particle simulation. Substantial differences in electron transport are found between the two different scenarios, and resultant electron precipitation patterns are compared. Such a comparison is valuable for interpreting low Earth-orbiting satellite observations of electron flux variation in response to the interaction with magnetospheric chorus waves.

scholarly journals Resonant diffusion of radiation belt energetic electrons by field-aligned propagation whistler-mode chorus waves

2008 ◽  
Vol 57 (12) ◽  
pp. 7937
Author(s):  
Ni Bin-Bin ◽  
Zhao Zheng-Yu ◽  
Gu Xu-Dong ◽  
Wang Feng
Keyword(s):  
Radiation Belt ◽  
Whistler Mode ◽  
Energetic Electrons ◽  
Chorus Waves

scholarly journals Repetitive emissions of rising-tone chorus waves in the inner magnetosphere

2020 ◽  
Author(s):  
Quanming Lu ◽  
Xueyi Wang ◽  
Lunjin Chen ◽  
Xinliang Gao ◽  
Yu Lin ◽  
...  
Keyword(s):  
Temperature Anisotropy ◽  
Inner Magnetosphere ◽  
Energetic Electrons ◽  
One Dimensional ◽  
Chorus Waves ◽  
Dipole Magnetic Field ◽  
Discrete And Continuous Spectra ◽  
Continuous Injection ◽  
Intense Injection ◽  
Frequency Chirping

Abstract Chorus waves are well known for their significant roles in the radiation belts of the Earth and other magnetized planets, including acceleration of electrons to relativistic energies, and precipitation of energetic electrons into the ionosphere to produce diffuse and pulsating aurora. They typically occur in the form of discrete and repetitive quasi-monochromatic emissions with a frequency chirping, which was discovered more than 50 years ago. However, until now there is still no satisfactory explanations for repetitive emissions of chorus waves. In this report, chorus emissions excited by energetic electrons with a temperature anisotropy are studied by both a one-dimensional \(\delta f\) simulation and theoretical model in a dipole magnetic field. The two models have unanimously demonstrated that a continuous injection of energetic electrons caused by an azimuthal drift is essential for the repetitive emissions of chorus waves. Consistent with satellite observations, both discrete and continuous spectra can be reproduced. An intense injection of energetic electrons will lead to a decrease of the time separation between the chorus elements, and the chorus emissions evolve from a discrete to a continuous spectrum when the injection is sufficiently strong.

Unexpected frequency-sweep reverse of subelements in chorus rising tone

2021 ◽  
Author(s):  
Si Liu ◽  
Zhonglei Gao
Keyword(s):  
Growth Phase ◽  
Electron Distribution ◽  
Linear Growth ◽  
Nonlinear Resonance ◽  
Nonlinear Process ◽  
Previous Theory ◽  
Frequency Sweep ◽  
Energetic Electrons ◽  
Similar Morphology ◽  
Chorus Waves

<p>Nonlinear resonance between energetic electrons and chorus waves is widely used to explain the frequency sweep of chorus, which predicts that rising tone elements are comprised by multiple subpackets with the frequency gradually increasing. Here we report two events that subelements with their frequencies downward chirping occur in rising tone chorus. The duration of those subelements is comparable with the regular subpackets, and their frequency sweep rates 6-12 kHz/s are consistent with previous theory and observations. Waveform of the subelement shows similar morphology to regular chorus element, consisting several finer structures "hyper-subpackets". We propose a possible scenario that the falling tone subelements are formed by nonlinear process with much shorter timescale. The starting frequency of each subelement controlled by the linear growth phase increases may because the electron distribution varies fast. This study provides new insight on chorus generation and also brings challenges.</p>

The influence of various frequency chorus waves on electron dynamics in radiation belts

2020 ◽  
Vol 64 (4) ◽  
pp. 890-897
Author(s):  
JiaBei He ◽  
YuYue Jin ◽  
FuLiang Xiao ◽  
ZhaoGuo He ◽  
Chang Yang ◽  
...  
Keyword(s):  
Radiation Belts ◽  
Electron Dynamics ◽  
Chorus Waves

scholarly journals Penetration of MeV electrons into the mesosphere accompanying pulsating aurorae

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Y. Miyoshi ◽  
K. Hosokawa ◽  
S. Kurita ◽  
S.-I. Oyama ◽  
Y. Ogawa ◽  
...  
Keyword(s):  
High Energy ◽  
Daily Basis ◽  
Maximum Energy ◽  
Energy Electron ◽  
High Energy Electron ◽  
Whistler Mode ◽  
Chorus Waves ◽  
Mesospheric Ozone ◽  
Field Lines ◽  
Eiscat Radar

AbstractPulsating aurorae (PsA) are caused by the intermittent precipitations of magnetospheric electrons (energies of a few keV to a few tens of keV) through wave-particle interactions, thereby depositing most of their energy at altitudes ~ 100 km. However, the maximum energy of precipitated electrons and its impacts on the atmosphere are unknown. Herein, we report unique observations by the European Incoherent Scatter (EISCAT) radar showing electron precipitations ranging from a few hundred keV to a few MeV during a PsA associated with a weak geomagnetic storm. Simultaneously, the Arase spacecraft has observed intense whistler-mode chorus waves at the conjugate location along magnetic field lines. A computer simulation based on the EISCAT observations shows immediate catalytic ozone depletion at the mesospheric altitudes. Since PsA occurs frequently, often in daily basis, and extends its impact over large MLT areas, we anticipate that the PsA possesses a significant forcing to the mesospheric ozone chemistry in high latitudes through high energy electron precipitations. Therefore, the generation of PsA results in the depletion of mesospheric ozone through high-energy electron precipitations caused by whistler-mode chorus waves, which are similar to the well-known effect due to solar energetic protons triggered by solar flares.

Analytic model of the energy distribution for energetic electrons in HiPIMS

2015 ◽  
Author(s):  
Sara Gallian ◽  
Jan Trieschmann ◽  
Thomas Mussenbrock ◽  
William N. G. Hitchon ◽  
Ralf Peter Brinkmann
Keyword(s):  
Energy Distribution ◽  
Analytic Model ◽  
Energetic Electrons
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