Resonant scattering of outer zone relativistic electrons by multiband EMIC waves and resultant electron loss time scales

2015 ◽  
Vol 120 (9) ◽  
pp. 7357-7373 ◽  
Author(s):  
Binbin Ni ◽  
Xing Cao ◽  
Zhengyang Zou ◽  
Chen Zhou ◽  
Xudong Gu ◽  
...  
Keyword(s):  
Time Scales ◽  
Outer Zone ◽  
Resonant Scattering ◽  
Relativistic Electrons ◽  
Electron Loss ◽  
Emic Waves

scholarly journals Radial diffusion modeling with empirical lifetimes: comparison with CRRES observations

2005 ◽  
Vol 23 (4) ◽  
pp. 1467-1471 ◽  
Author(s):  
Y. Y. Shprits ◽  
R. M. Thorne ◽  
G. D. Reeves ◽  
R. Friedel
Keyword(s):  
Diffusion Model ◽  
Radiation Effects ◽  
Outer Zone ◽  
Recovery Phase ◽  
Decay Rates ◽  
Radial Diffusion ◽  
Main Phase ◽  
Relativistic Electrons ◽  
Storm Main Phase ◽  
Order Of Magnitude

Abstract. A time dependent radial diffusion model is used to quantify the competing effects of inward radial diffusion and losses on the distribution of the outer zone relativistic electrons. The rate of radial diffusion is parameterized by Kp with the loss time as an adjustable parameter. Comparison with HEEF data taken over 500 Combined Release and Radiation Effects Satellite (CRRES) orbits indicates that 1-MeV electron lifetimes near the peak of the outer zone are less than a day during the storm main phase and few days under less disturbed conditions. These values are comparable to independent estimates of the storm time loss rate due to scattering by EMIC waves and chorus emission, and also provide an acceptable representation of electron decay rates following the storm time injection. Although our radial diffusion model, with data derived lifetimes, is able to simulate many features of the variability of outer zone fluxes and predicts fluxes within one order of magnitude accuracy for most of the storms and L values, it fails to reproduce the magnitude of flux changes and the gradual build up of fluxes observed during the recovery phase of many storms. To address these differences future modeling should include an additional local acceleration source and also attempt to simulate the pronounced loss of electrons during the main phase of certain storms.

scholarly journals Trapping and amplification of unguided mode EMIC waves in the radiation belt

2021 ◽  
Author(s):  
Geng Wang ◽  
Zhonglei Gao ◽  
Mingyu Wu ◽  
Guoqiang Wang ◽  
Sudong Xiao ◽  
...  
Keyword(s):  
Radiation Belt ◽  
Abundance Ratio ◽  
Relativistic Electrons ◽  
Scattering Loss ◽  
Propagation Behavior ◽  
Guided Mode ◽  
Waves Propagation ◽  
Spatial Locations ◽  
First Time ◽  
Emic Waves

Abstract Electromagnetic ion cyclotron (EMIC) waves can cause the scattering loss of the relativistic electrons in the earth's radiation belt. They can be classified into the guided mode and the unguided mode, according to waves propagation behavior. The guided mode waves have been widely investigated in the radiation belt, but the observation of the unguided mode waves have not been expected. Based on the observations of Van Allen Probes, we demonstrate for the first time the existence of the intense unguided mode EMIC waves. The reflection interface formed by the spatial locations of local helium cutoff frequencies can be nearly parallel to the equatorial plane when the proton abundance ratio decreases sharply with L-shell. This structure combined with the anisotropic hot protons can lead to the trapping and significant amplification of the unguided mode waves. These results may help to understand the nature of EMIC waves in the radiation belt.

scholarly journals Relativistic electrons in the outer-zone: An 11 year cycle; Their relation to the solar wind

1996 ◽  
Author(s):  
R. D. Belian ◽  
T. E. Cayton ◽  
R. A. Christensen ◽  
J. C. Ingraham ◽  
M. M. Meier ◽  
...  
Keyword(s):  
Solar Wind ◽  
Outer Zone ◽  
Relativistic Electrons

Statistical Investigation of the Efficiency of EMIC Waves in Precipitating Relativistic Electrons

2018 ◽  
Vol 123 (8) ◽  
pp. 6223-6230 ◽  
Author(s):  
Murong Qin ◽  
Mary Hudson ◽  
Robyn Millan ◽  
Leslie Woodger ◽  
Sapna Shekhar
Keyword(s):  
Statistical Investigation ◽  
Relativistic Electrons ◽  
Emic Waves

scholarly journals Energetic outer zone electron loss timescales during low geomagnetic activity

2006 ◽  
Vol 111 (A5) ◽  
Author(s):  
Nigel P. Meredith ◽  
Richard B. Horne ◽  
Sarah A. Glauert ◽  
Richard M. Thorne ◽  
Danny Summers ◽  
...  
Keyword(s):  
Geomagnetic Activity ◽  
Outer Zone ◽  
Electron Loss

TIME-DEPENDENT SSC COOLING EFFECTS ON BLAZAR EMISSION

2014 ◽  
Vol 28 ◽  
pp. 1460181
Author(s):  
MICHAEL ZACHARIAS ◽  
REINHARD SCHLICKEISER
Keyword(s):  
Time Scales ◽  
Doubling Time ◽  
Spectral Energy Distribution ◽  
Nonlinear Behavior ◽  
Time Dependent ◽  
Spectral Energy ◽  
Relativistic Electrons ◽  
Linear Approach ◽  
Standard Linear ◽  
Cooling Effects

Blazars are among the most violent sources in the cosmos exhibiting flaring states with remarkably different variability time scales. Especially rapid flares with flux doubling time scales of the order of minutes have been puzzling for quite some time. Many modeling attempts use the well known linear and steady-state scenario for the cooling and emission processes in the jet, albeit the obvious strongly time-dependent nature of flares. Due to the feedback of the self-produced synchrotron radiation with additional scattering by the relativistic electrons, the synchrotron-self Compton (SSC) effect is inherently time-dependent. Recently, an analytical analysis on the effects of this nonlinear behavior has been presented. Here, we summarize these results concerning the effect of the time-dependent SSC cooling on the spectral energy distribution (SED), and the synchrotron lightcurves of blazars. For that, we calculated analytically the synchrotron, SSC and external Compton (EC) component of the SED, giving remarkably different spectral features compared to the standard linear approach. The resulting fluxes strongly depend on the parameters, and SSC might have a strong effect even in sources with strong external photon fields (such as FSRQs). For the synchrotron lightcurve we considered the effects of retardation, including the geometry of the source. The retardation might smear out some effects of the time-dependent cooling, but since lightcurves and SEDs have to be fitted simultaneously with the same set of parameters, the results give nonetheless important clues about the source. Thus, we argue for a wide utilization of the time-dependent treatment in modeling (especially rapid) blazar flares, since it accounts for features in the SED and the lightcurves that are usually accounted for by introducing several breaks in the electron distribution without any physical justification.

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