scholarly journals Stormtime dynamics of the global thermosphere and equatorial ionosphere

2009 ◽  
Vol 27 (5) ◽  
pp. 2035-2044 ◽  
Author(s):  
W. J. Burke ◽  
C. Y. Huang ◽  
R. D. Sharma
Keyword(s):  
Equatorial Ionosphere ◽  
Magnetic Storms ◽  
Main Phase ◽  
New Method ◽  
Sufficient Time ◽  
Quiet Time ◽  
Early Recovery ◽  
Plasma Bubbles ◽  
Equatorial Plasma Bubbles ◽  
Phase Activity

Abstract. During magnetic storms the development of equatorial plasma bubbles (EPBs) and distributions of thermospheric densities are strongly influenced by the histories of imposed magnetospheric electric (εM) fields. Periods of intense EPB activity driven by penetration εM fields in the main phase are followed by their worldwide absence during recovery. A new method is applied to estimate global thermospheric energy (Eth) budgets from orbit-averaged densities measured by accelerometers on polar-orbiting satellites. During the main phase of storms Eth increases as long as the stormtime εM operates, then exponentially decays toward quiet-time values during early recovery. Some fraction of the energy deposited at high magnetic latitudes during the main phase propagates into the subauroral ionosphere-thermosphere where it affects chemical and azimuthal-wind dynamics well into recovery. We suggest a scenario wherein fossils of main phase activity inhibit full restoration of quiet-time dayside dynamos and pre-reversal enhancements of upward plasma drifts near dusk denying bottomside irregularities sufficient time to grow into EPBs.

scholarly journals Occurrence of Equatorial Plasma Bubbles during Intense Magnetic Storms

2011 ◽  
Vol 2011 ◽  
pp. 1-10 ◽  
Author(s):  
Chao-Song Huang
Keyword(s):  
Electric Field ◽  
Magnetic Storms ◽  
Ion Density ◽  
Plasma Bubbles ◽  
Defense Meteorological Satellite Program ◽  
Equatorial Plasma Bubbles ◽  
Evening Sector ◽  
Plasma Depletions ◽  
Meteorological Satellite ◽  
The Imf

An important issue in low-latitude ionospheric space weather is how magnetic storms affect the generation of equatorial plasma bubbles. In this study, we present the measurements of the ion density and velocity in the evening equatorial ionosphere by the Defense Meteorological Satellite Program (DMSP) satellites during 22 intense magnetic storms. The DMSP measurements show that deep ion density depletions (plasma bubbles) are generated after the interplanetary magnetic field (IMF) turns southward. The time delay between the IMF southward turning and the first DMSP detection of plasma depletions decreases with the minimum value of the IMFBz, the maximum value of the interplanetary electric field (IEF)Ey, and the magnitude of the Dst index. The results of this study provide strong evidence that penetration electric field associated with southward IMF during the main phase of magnetic storms increases the generation of equatorial plasma bubbles in the evening sector.

scholarly journals Dynamics Ionospheric Plasma Bubbles Measured by Optical Imaging System

2015 ◽  
Vol 20 (1) ◽  
pp. 20-27
Author(s):  
Narayan P. Chapagain
Keyword(s):  
Imaging System ◽  
Equatorial Ionosphere ◽  
Navigation Systems ◽  
Plasma Bubble ◽  
Central Pacific ◽  
Central Pacific Ocean ◽  
Plasma Bubbles ◽  
Christmas Island ◽  
Equatorial Plasma Bubbles ◽  
Plasma Depletions

Deep plasma depletions during the nighttime period in the equatorial ionosphere (referred to as equatorial plasma bubbles –EPBs) can significantly affect communications and navigation systems. In this study, we present the image measurements of plasma bubble from Christmas Island (2.1°N, 157.4°W, dip latitude 2.8°N) in the central Pacific Ocean. These observations were made during September-October 1995 using a Utah State University (USU) CCD imaging system measured at ~280 km altitude. Well-defined magnetic field-aligned plasma depletions were observed for 18 nights, including strong post-midnight fossilized structures, enabling detailed measurements of their morphology and dynamics. We also estimate zonal velocity of the plasma bubbles from available images. The zonal drift velocity of the EPBs is a very important parameter for the understanding and modeling of the electrodynamics of the equatorial ionosphere and for the predictions of ionospheric irregularities. The eastward zonal drift velocities were around 90-100 m/s prior to local midnight, and decreases during the post-midnight period that persisted until dawn.Journal of Institute of Science and Technology, 2015, 20(1): 20-27

scholarly journals An analysis of the quiet time day-to-day variability in the formation of postsunset equatorial plasma bubbles in the Southeast Asian region

2014 ◽  
Vol 119 (4) ◽  
pp. 3206-3223 ◽  
Author(s):  
B. A. Carter ◽  
E. Yizengaw ◽  
J. M. Retterer ◽  
M. Francis ◽  
M. Terkildsen ◽  
...  
Keyword(s):  
Southeast Asian ◽  
Quiet Time ◽  
Plasma Bubbles ◽  
Asian Region ◽  
Equatorial Plasma Bubbles

scholarly journals Specific interplanetary conditions for CIR-, Sheath-, and ICME-induced geomagnetic storms obtained by double superposed epoch analysis

2010 ◽  
Vol 28 (12) ◽  
pp. 2177-2186 ◽  
Author(s):  
Yu. I. Yermolaev ◽  
N. S. Nikolaeva ◽  
I. G. Lodkina ◽  
M. Yu. Yermolaev
Keyword(s):  
Large Scale ◽  
Geomagnetic Storms ◽  
Magnetic Cloud ◽  
Magnetic Storms ◽  
Main Phase ◽  
Corotating Interaction Region ◽  
Superposed Epoch Analysis ◽  
Epoch Analysis ◽  
Archive Data ◽  
Scale Types

Abstract. A comparison of specific interplanetary conditions for 798 magnetic storms with Dst <−50 nT during 1976–2000 was made on the basis of the OMNI archive data. We categorized various large-scale types of solar wind as interplanetary drivers of storms: corotating interaction region (CIR), Sheath, interplanetary CME (ICME) including both magnetic cloud (MC) and Ejecta, separately MC and Ejecta, and "Indeterminate" type. The data processing was carried out by the method of double superposed epoch analysis which uses two reference times (onset of storm and minimum of Dst index) and makes a re-scaling of the main phase of the storm in a such way that all storms have equal durations of the main phase in the new time reference frame. This method reproduced some well-known results and allowed us to obtain some new results. Specifically, obtained results demonstrate that (1) in accordance with "output/input" criteria the highest efficiency in generation of magnetic storms is observed for Sheath and the lowest one for MC, and (2) there are significant differences in the properties of MC and Ejecta and in their efficiencies.

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.

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