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>

Wave–particle interactions and energetic tail formation in the electron distribution

1986 ◽  
Vol 64 (8) ◽  
pp. 977-985
Author(s):  
J. Meyer
Keyword(s):  
Raman Scattering ◽  
Electron Distribution ◽  
Stimulated Raman Scattering ◽  
Particle Interactions ◽  
Energetic Electrons ◽  
Wave Particle Interactions ◽  
Stimulated Raman

Both the stimulated Raman scattering and the two-plasmon decay instabilities are shown to generate energetic electrons by wave–particle interactions. The results of computer particle stimulations and a variety of experiments are discussed and compared. Many predictions derived from simulations are verified by experimental observations.

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 Inhibition of the Progesterone Nuclear Receptor during the Bone Linear Growth Phase Increases Peak Bone Mass in Female Mice

PLoS ONE ◽  
2010 ◽  
Vol 5 (7) ◽  
pp. e11410 ◽  
Author(s):  
Wei Yao ◽  
Weiwei Dai ◽  
Mohammad Shahnazari ◽  
Aaron Pham ◽  
Zhiqiang Chen ◽  
...  
Keyword(s):  
Bone Mass ◽  
Nuclear Receptor ◽  
Growth Phase ◽  
Peak Bone Mass ◽  
Linear Growth ◽  
Female Mice

Tubulin in sea urchin embryonic cilia: post-translational modifications during regeneration

1992 ◽  
Vol 101 (4) ◽  
pp. 837-845 ◽  
Author(s):  
R.E. Stephens
Keyword(s):  
Monoclonal Antibody ◽  
Sea Urchin ◽  
Growth Phase ◽  
Linear Growth ◽  
Major Protein ◽  
Post Translational Modifications ◽  
Alpha Tubulin ◽  
Ciliary Membrane ◽  
Membrane Matrix ◽  
Matrix Fraction

Tubulin is the major protein found in the membrane/periaxonemal matrix fraction of mature sea urchin embryonic cilia but its distribution and possible function during ciliary assembly are unknown. Hypertonic salt may be used to deciliate the embryos, allowing synchronous regrowth of cilia and subsequent deciliation of the regenerating embryos at various times. During the earliest stages of regeneration, the amounts of tubulin in the axoneme and membrane/matrix fractions are nearly equal, but the proportion of tubulin in the axoneme fraction increases coincident with the quasi-linear growth phase while the membrane/matrix tubulin remains constant. Antibodies to tyrosinated and detyrosinated alpha-tubulin show that both the membrane/matrix and axonemal tubulin fractions are primarily unmodified (i.e. tyrosinated) at the earliest stages of regeneration but are progressively and equally detyrosinated coincident with regeneration, approaching a final level of 50% C-terminal Glu. A monoclonal antibody to acetylated alpha-tubulin reveals that both tubulin fractions are equally and maximally acetylated at relatively early stages of regeneration. In contrast, three-times-repolymerized tubulin from either unfertilized eggs or midgastrula embryos is primarily tyrosinated (greater than 97%) and not detectably acetylated. These data suggest that membrane/matrix tubulin is a precursor to axonemal tubulin and that acetylation and detyrosination may be involved in partitioning tubulin among cytoplasmic, ciliary membrane/matrix, and 9 + 2 compartments.

scholarly journals Time-dependent modeling of particles and electromagnetic fields during the substorm growth phase: Anisotropy of energetic electrons

1999 ◽  
Vol 104 (A5) ◽  
pp. 10205-10220 ◽  
Author(s):  
P. K. Toivanen ◽  
T. I. Pulkkinen ◽  
R. H. W. Friedel ◽  
G. D. Reeves ◽  
A. Korth ◽  
...  
Keyword(s):  
Electromagnetic Fields ◽  
Growth Phase ◽  
Time Dependent ◽  
Phase Anisotropy ◽  
Energetic Electrons

scholarly journals Diffusive transport of energetic electrons in the solar corona: X-ray and radio diagnostics

2018 ◽  
Vol 610 ◽  
pp. A6 ◽  
Author(s):  
S. Musset ◽  
E. P. Kontar ◽  
N. Vilmer
Keyword(s):  
Solar Corona ◽  
Free Path ◽  
Electron Distribution ◽  
Transport Model ◽  
Imaging Spectroscopy ◽  
Mean Free Path ◽  
Diffusive Transport ◽  
X Rays ◽  
Energetic Electrons ◽  
X Ray

Context. Imaging spectroscopy in X-rays with RHESSI provides the possibility to investigate the spatial evolution of X-ray emitting electron distribution and therefore, to study transport effects on energetic electrons during solar flares. Aims. We study the energy dependence of the scattering mean free path of energetic electrons in the solar corona. Methods. We used imaging spectroscopy with RHESSI to study the evolution of energetic electrons distribution in various parts of the magnetic loop during the 2004 May 21 flare. We compared these observations with the radio observations of the gyrosynchrotron radiation of the same flare and with the predictions of a diffusive transport model. Results. X-ray analysis shows a trapping of energetic electrons in the corona and a spectral hardening of the energetic electron distribution between the top of the loop and the footpoints. Coronal trapping of electrons is stronger for radio-emitting electrons than for X-ray-emitting electrons. These observations can be explained by a diffusive transport model. Conclusions. We show that the combination of X-ray and radio diagnostics is a powerful tool to study electron transport in the solar corona in different energy domains. We show that the diffusive transport model can explain our observations, and in the range 25–500 keV, the scattering mean free path of electrons decreases with electron energy. We can estimate for the first time the scattering mean free path dependence on energy in the corona.

Richtmyer–Meshkov instability on a quasi-single-mode interface

2019 ◽  
Vol 872 ◽  
pp. 729-751 ◽  
Author(s):  
Yu Liang ◽  
Zhigang Zhai ◽  
Juchun Ding ◽  
Xisheng Luo
Keyword(s):  
Nonlinear Model ◽  
Small Amplitude ◽  
Linear Growth ◽  
Single Mode ◽  
High Order ◽  
Initial Amplitude ◽  
Previous Theory ◽  
Weakly Nonlinear ◽  
Nonlinear Stage ◽  
Amplitude Growth

Experiments on Richtmyer–Meshkov instability of quasi-single-mode interfaces are performed. Four quasi-single-mode air/$\text{SF}_{6}$ interfaces with different deviations from the single-mode one are generated by the soap film technique to evaluate the effects of high-order modes on amplitude growth in the linear and weakly nonlinear stages. For each case, two different initial amplitudes are considered to highlight the high-amplitude effect. For the single-mode and saw-tooth interfaces with high initial amplitude, a cavity is observed at the spike head, providing experimental evidence for the previous numerical results for the first time. For the quasi-single-mode interfaces, the fundamental mode is the dominant one such that it determines the amplitude linear growth, and subsequently the impulsive theory gives a reasonable prediction of the experiments by introducing a reduction factor. The discrepancy in linear growth rates between the experiment and the prediction is amplified as the quasi-single-mode interface deviates more severely from the single-mode one. In the weakly nonlinear stage, the nonlinear model valid for a single-mode interface with small amplitude loses efficacy, which indicates that the effects of high-order modes on amplitude growth must be considered. For the saw-tooth interface with small amplitude, the amplitudes of the first three harmonics are extracted from the experiment and compared with the previous theory. The comparison proves that each initial mode develops independently in the linear and weakly nonlinear stages. A nonlinear model proposed by Zhang & Guo (J. Fluid Mech., vol. 786, 2016, pp. 47–61) is then modified by considering the effects of high-order modes. The modified model is proved to be valid in the weakly nonlinear stage even for the cases with high initial amplitude. More high-order modes are needed to match the experiment for the interfaces with a more severe deviation from the single-mode one.

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