Equatorial plasma bubbles zonal velocity in the monthly variations over Southeast Asia

2019 ◽  
Author(s):  
I. Sarudin ◽  
N. S. A. Hamid ◽  
M. Abdullah ◽  
S. M. Buhari
Keyword(s):  
Southeast Asia ◽  
Plasma Bubbles ◽  
Equatorial Plasma Bubbles ◽  
Zonal Velocity ◽  
Monthly Variations

scholarly journals Zonal velocity of the equatorial plasma bubbles over Kolhapur, India

2013 ◽  
Vol 31 (11) ◽  
pp. 2077-2084 ◽  
Author(s):  
D. P. Nade ◽  
A. K. Sharma ◽  
S. S. Nikte ◽  
P. T. Patil ◽  
R. N. Ghodpage ◽  
...  
Keyword(s):  
Ionospheric Plasma ◽  
Universal Time ◽  
Low Latitude ◽  
Plasma Bubbles ◽  
Standard Time ◽  
Latitude Station ◽  
Equatorial Plasma Bubbles ◽  
Evening Sector ◽  
Zonal Velocity ◽  
Good Agreement

Abstract. This paper presents the observations of zonal drift velocities of equatorial ionospheric plasma bubbles and their comparison with model values. These velocities are determined by nightglow OI 630.0 nm images. The nightglow observations have been carried out from the low latitude station Kolhapur (16.8° N, 74.2° E; 10.6° N dip lat.) during clear moonless nights. Herein we have presented the drift velocities of equatorial plasma bubbles for the period of February–April 2011. Out of 80 nights, 39 showed the occurrence of equatorial plasma bubbles (49%). These 39 nights correspond to magnetically quiet days (ΣKp < 26). The average eastward zonal velocities (112 ± 10 m s−1) of equatorial plasma bubbles increased from evening sector to 21:00 IST (Indian Standard Time = Universal Time + 05:30:00 h), reach maximum about 165 ± 30 m s−1 and then decreases with time. The calculated velocities are in good agreement with that of recently reported values obtained with models with occasional differences; possible mechanisms of which are discussed.

scholarly journals Implication of tidal forcing effects on the zonal variation of solstice equatorial plasma bubbles

2020 ◽  
Author(s):  
Loren C. Chang ◽  
Cornelius Csar Jude Hisole Salinas ◽  
Yi-Chung Chiu ◽  
McArthur Jones ◽  
Chi-Kuang Chao ◽  
...  
Keyword(s):  
Tidal Forcing ◽  
Plasma Bubbles ◽  
Equatorial Plasma Bubbles

scholarly journals Seasonal-longitudinal variability of equatorial plasma bubbles

2004 ◽  
Vol 22 (9) ◽  
pp. 3089-3098 ◽  
Author(s):  
W. J. Burke ◽  
C. Y. Huang ◽  
L. C. Gentile ◽  
L. Bauer
Keyword(s):  
Solar Cycle ◽  
Phase Shifts ◽  
Linear Growth Rate ◽  
Cycle Phase ◽  
Loss Cone ◽  
Plasma Bubbles ◽  
Equatorial Plasma Bubbles ◽  
Evening Sector ◽  
Radiation Belt Electrons ◽  
Longitudinal Variability

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.

scholarly journals Filamentary Alfvénic structures excited at the edges of equatorial plasma bubbles

2007 ◽  
Vol 25 (10) ◽  
pp. 2159-2165 ◽  
Author(s):  
R. Pottelette ◽  
M. Malingre ◽  
J. J. Berthelier ◽  
E. Seran ◽  
M. Parrot
Keyword(s):  
Alfven Waves ◽  
Alfvén Waves ◽  
Plasma Bubble ◽  
Plasma Bubbles ◽  
Wave Measurements ◽  
Demeter Satellite ◽  
Equatorial Plasma Bubbles ◽  
Background Magnetic Field ◽  
Gravity Driven ◽  
Displacement Currents

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.

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