Periodic spacing between consecutive equatorial plasma bubbles

2010 ◽  
Vol 37 (14) ◽  
pp. n/a-n/a ◽  
Author(s):  
J. J. Makela ◽  
S. L. Vadas ◽  
R. Muryanto ◽  
T. Duly ◽  
G. Crowley
2020 ◽  
Author(s):  
Loren C. Chang ◽  
Cornelius Csar Jude Hisole Salinas ◽  
Yi-Chung Chiu ◽  
McArthur Jones ◽  
Chi-Kuang Chao ◽  
...  

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.


2007 ◽  
Vol 25 (10) ◽  
pp. 2159-2165 ◽  
Author(s):  
R. Pottelette ◽  
M. Malingre ◽  
J. J. Berthelier ◽  
E. Seran ◽  
M. Parrot

Abstract. Recent observations performed by the French DEMETER satellite at altitudes of about 710 km suggest that the generation of equatorial plasma bubbles correlates with the presence of filamentary structures of field aligned currents carried by Alfvén waves. These localized structures are located at the bubble edges. We study the dynamics of the equatorial plasma bubbles, taking into account that their motion is dictated by gravity driven and displacement currents. Ion-polarization currents appear to be crucial for the accurate description of the evolution of plasma bubbles in the high altitude ionosphere. During their eastward/westward motion the bubbles intersect gravity driven currents flowing transversely with respect to the background magnetic field. The circulation of these currents is prohibited by large density depressions located at the bubble edges acting as perfect insulators. As a result, in these localized regions the transverse currents have to be locally closed by field aligned currents. Such a physical process generates kinetic Alfvén waves which appear to be stationary in the plasma bubble reference frame. Using a two-dimensional model and "in situ" wave measurements on board the DEMETER spacecraft, we give estimates for the magnitude of the field aligned currents and the associated Alfvén fields.


2017 ◽  
Vol 7 ◽  
pp. A3 ◽  
Author(s):  
Sergio Magdaleno ◽  
Miguel Herraiz ◽  
David Altadill ◽  
Benito A. de la Morena

2021 ◽  
Vol 5 (4) ◽  
pp. 1-9
Author(s):  
K. K. Ajith ◽  
◽  
S. Tulasi Ram ◽  
GuoZhu Li ◽  
M. Yamamoto ◽  
...  

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