scholarly journals Comment on ‘Radiation belt electrons: Structure of the loss cone’ by W. N. Spjeldvik

1978 ◽  
Vol 83 (A1) ◽  
pp. 225-225 ◽  
Author(s):  
M. Walt ◽  
G. T. Davidson
2020 ◽  
Author(s):  
Yang Zhang ◽  
Binbin Ni ◽  
Xudong Gu ◽  
Yuri Shprits ◽  
Song Fu ◽  
...  

<p><span>Magnetospheric chorus is known to play a significant role in the acceleration and loss of radiation belt electrons. Interactions of chorus waves with radiation belt particles are commonly evaluated using quasi-linear diffusion codes that rely on statistical models, which might not accurately provide the instantaneous global wave distribution from limited in-situ wave measurements. Thus, a novel technique capable of inferring wave amplitudes from POES particle measurements, with an extensive coverage of L-shell and magnetic local time, has been established to obtain event-specific, global dynamic evolutions of chorus waves. This study, using 5 years of POES electron data, further improves the technique, and enables us to subsequently infer the chorus wave amplitudes for all useful data points (removing the electrons which were in the drift loss cone) and to construct the global distribution of lower-band chorus wave intensity. The results obtained from the improved technique reproduce Van Allen Probes in-situ observations of chorus waves reasonably well and reconstruct the major features of the global distribution of chorus waves. We demonstrate that such a data-based, dynamic model can provide near-real-time estimates of chorus wave intensity on a global scale for any time period when POES data are available, which cannot be obtained from in-situ wave measurements by equatorial satellites alone, but is crucial for quantifying the  dynamics of the radiation belt electrons.</span></p>


2004 ◽  
Vol 22 (9) ◽  
pp. 3089-3098 ◽  
Author(s):  
W. J. Burke ◽  
C. Y. Huang ◽  
L. C. Gentile ◽  
L. Bauer

Abstract. We compare seasonal and longitudinal distributions of more than 8300 equatorial plasma bubbles (EPBs) observed during a full solar cycle from 1989-2000 with predictions of two simple models. Both models are based on considerations of parameters that influence the linear growth rate, γRT, of the generalized Rayleigh-Taylor instability in the context of finite windows of opportunity available during the prereversal enhancement near sunset. These parameters are the strength of the equatorial magnetic field, Beq, and the angle, α, it makes with the dusk terminator line. The independence of α and Beq from the solar cycle phase justifies our comparisons. We have sorted data acquired during more than 75000 equatorial evening-sector passes of polar-orbiting Defense Meteorological Satellite Program (DMSP) satellites into 24 longitude and 12 one-month bins, each containing ~250 samples. We show that: (1) in 44 out of 48 month-longitude bins EPB rates are largest within 30 days of when α=0°; (2) unpredicted phase shifts and asymmetries appear in occurrence rates at the two times per year when α≈0°; (3) While EPB occurrence rates vary inversely with Beq, the relationships are very different in regions where Beq is increasing and decreasing with longitude. Results (2) and (3) indicate that systematic forces not considered by the two models can become important. Damping by interhemispheric winds appears to be responsible for phase shifts in maximum rates of EPB occurrence from days when α=0°. Low EPB occurrence rates found at eastern Pacific longitudes suggest that radiation belt electrons in the drift loss cone reduce γRT by enhancing E-layer Pedersen conductances. Finally, we analyze an EPB event observed during a magnetic storm at a time and place where α≈-27°, to illustrate how electric-field penetration from high latitudes can overwhelm the damping effects of weak gradients in Pedersen conductance near dusk.


2011 ◽  
Vol 73 (7-8) ◽  
pp. 785-795 ◽  
Author(s):  
Qiuhua Zheng ◽  
Mei-Ching Fok ◽  
Jay Albert ◽  
Richard B. Horne ◽  
Nigel P. Meredith

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