Bibliography

Low-latitude plasma blobs above Africa: Exploiting GOLD and multi-satellite in situ measurements

Low-latitude plasma blobs are localized density enhancements of electron density that are occasionally observed in the night-time tropical ionosphere. Two-dimensional (2D) imaging of this phenomenon has been rare and frequently restricted to Central/South America, which is densely covered with ground-based airglow imagers and Global Navigation Satellite System (GNSS) receivers. In Africa, on the contrary, no 2D image of a blob has been reported. Here we present two low-latitude blob events above Africa, one in the Northern summer and the other in winter, in the 2-dimensional Far-UltraViolet (FUV) images from the Global-scale Observations of the Limb and Disk (GOLD) mission. Additionally, multiple satellites (four spacecraft per event) on the Low-Earth-Orbit (LEO) encountered the blob events, some within the GOLD images and some outside. The LEO data support the robustness of GOLD observations and bridge time gaps between the consecutive images. Properties of the two blob events above Africa generally support the conclusions in a previous case study for Central/South America. Plasma therein exhibited higher O+ fraction and faster ion flow toward outer L-shells than the ambient. The blobs were conjugate to locally intensified Equatorial Ionization Anomaly crests without conspicuous equatorward-westward propagation. Our results demonstrate the usefulness of GOLD and multiple LEO satellites in monitoring the ionosphere above Africa, which is a fascinating laboratory of low-latitude electrodynamics but still waiting for more observatories to be deployed.

Park, Jaeheung; Min, Kyoung; Eastes, Richard; Chao, Chi; Kim, Hee-Eun; Lee, Junchan; Sohn, Jongdae; Ryu, Kwangsun; Seo, Hoonkyu; Yoo, Ji-Hyeon; Lee, Seunguk; Woo, Changho; Kim, Eo-Jin;

Published by: Advances in Space Research      Published on: may

YEAR: 2022     DOI: 10.1016/j.asr.2022.05.021

COSMIC-2; GOLD; ICON; Low-latitude blobs; NextSat-1; swarm

Signatures of Equatorial Plasma Bubbles and Ionospheric Scintillations from Magnetometer and GNSS Observations in the Indian Longitudes during the Space Weather Events of Early September 2017

Scintillation due to ionospheric plasma irregularities remains a challenging task for the space science community as it can severely threaten the dynamic systems relying on space-based navigation services. In the present paper, we probe the ionospheric current and plasma irregularity characteristics from a latitudinal arrangement of magnetometers and Global Navigation Satellite System (GNSS) stations from the equator to the far low latitude location over the Indian longitudes, during the severe space weather events of 6–10 September 2017 that are associated with the strongest and consecutive solar flares in the 24th solar cycle. The night-time influence of partial ring current signatures in ASYH and the daytime influence of the disturbances in the ionospheric E region electric currents (Diono) are highlighted during the event. The total electron content (TEC) from the latitudinal GNSS observables indicate a perturbed equatorial ionization anomaly (EIA) condition on 7 September, due to a sequence of M-class solar flares and associated prompt penetration electric fields (PPEFs), whereas the suppressed EIA on 8 September with an inverted equatorial electrojet (EEJ) suggests the driving disturbance dynamo electric current (Ddyn) corresponding to disturbance dynamo electric fields (DDEFs) penetration in the E region and additional contributions from the plausible storm-time compositional changes (O/N2) in the F-region. The concurrent analysis of the Diono and EEJ strengths help in identifying the pre-reversal effect (PRE) condition to seed the development of equatorial plasma bubbles (EPBs) during the local evening sector on the storm day. The severity of ionospheric irregularities at different latitudes is revealed from the occurrence rate of the rate of change of TEC index (ROTI) variations. Further, the investigations of the hourly maximum absolute error (MAE) and root mean square error (RMSE) of ROTI from the reference quiet days’ levels and the timestamps of ROTI peak magnitudes substantiate the severity, latitudinal time lag in the peak of irregularity, and poleward expansion of EPBs and associated scintillations. The key findings from this study strengthen the understanding of evolution and the drifting characteristics of plasma irregularities over the Indian low latitudes.

Vankadara, Ram; Panda, Sampad; Amory-Mazaudier, Christine; Fleury, Rolland; Devanaboyina, Venkata; Pant, Tarun; Jamjareegulgarn, Punyawi; Haq, Mohd; Okoh, Daniel; Seemala, Gopi;

Published by: Remote Sensing      Published on: jan

YEAR: 2022     DOI: 10.3390/rs14030652

space weather; equatorial plasma bubbles; ionospheric irregularity; global navigation satellite system; magnetometer; poleward drift; rate of change of TEC index; scintillations; storm-time electric currents

APL JANUS System Progress on Commercial Suborbital Launch Vehicles: Moving the Laboratory Environment to Near Space

Smith, Todd; Hacala, Ryan; Hohlfeld, Erik; Edens, Weston; Hibbitts, Charles; Paxton, Larry; Arnold, Steven; Westlake, Joseph; Rymer, Abigail; Chacos, Al; , others;

Published by: Gravitational and Space Research      Published on:

YEAR: 2021     DOI:

Diffuse and Pulsating Aurora

This chapter reviews fundamental properties and recent advances of diffuse and pulsating aurora. Diffuse and pulsating aurora often occurs on closed field lines and involves energetic electron precipitation by wave-particle interaction. After summarizing the definition, large-scale morphology, types of pulsation, and driving processes, we review observation techniques, occurrence, duration, altitude, evolution, small-scale structures, fast modulation, relation to high-energy precipitation, the role of ECH waves, reflected and secondary electrons, ionosphere dynamics, and simulation of wave-particle interaction. Finally we discuss open questions of diffuse and pulsating aurora.

Nishimura, Yukitoshi; Lessard, Marc; Katoh, Yuto; Miyoshi, Yoshizumi; Grono, Eric; Partamies, Noora; Sivadas, Nithin; Hosokawa, Keisuke; Fukizawa, Mizuki; Samara, Marilia; Michell, Robert; Kataoka, Ryuho; Sakanoi, Takeshi; Whiter, Daniel; Oyama, Shin-ichiro; Ogawa, Yasunobu; Kurita, Satoshi;

Published by: Space Science Reviews      Published on: 01/2020

YEAR: 2020     DOI: 10.1007/s11214-019-0629-3

Hybrid-Vlasov simulation of auroral proton precipitation in the cusps: Comparison of northward and southward interplanetary magnetic field driving

Particle precipitation is a central aspect of space weather, as it strongly couples the magnetosphere and the ionosphere and can be responsible for radio signal disruption at high

Grandin, Maxime; Turc, Lucile; Battarbee, Markus; Ganse, Urs; Johlander, Andreas; Pfau-Kempf, Yann; Dubart, Maxime; Palmroth, Minna;

Published by: Journal of space weather and space climate      Published on:

YEAR: 2020     DOI: 10.1051/swsc/2020053

Space Weather Modeling Capabilities Assessment: Auroral Precipitation and High-Latitude Ionospheric Electrodynamics

As part of its International Capabilities Assessment effort, the Community Coordinated Modeling Center initiated several working teams, one of which is focused on the validation of models and methods for determining auroral electrodynamic parameters, including particle precipitation, conductivities, electric fields, neutral density and winds, currents, Joule heating, auroral boundaries, and ion outflow. Auroral electrodynamic properties are needed as input to space weather models, to test and validate the accuracy of physical models, and to provide needed information for space weather customers and researchers. The working team developed a process for validating auroral electrodynamic quantities that begins with the selection of a set of events, followed by construction of ground truth databases using all available data and assimilative data analysis techniques. Using optimized, predefined metrics, the ground truth data for selected events can be used to assess model performance and improvement over time. The availability of global observations and sophisticated data assimilation techniques provides the means to create accurate ground truth databases routinely and accurately.

Robinson, Robert; Zhang, Yongliang; Garcia-Sage, Katherine; Fang, Xiaohua; Verkhoglyadova, Olga; Ngwira, Chigomezyo; Bingham, Suzy; Kosar, Burcu; Zheng, Yihua; Kaeppler, Stephen; Liemohn, Michael; Weygand, James; Crowley, Geoffrey; Merkin, Viacheslav; McGranaghan, Ryan; Mannucci, Anthony;

Published by: Space Weather      Published on: 01/2019

YEAR: 2019     DOI: 10.1029/2018SW002127

Review of the accomplishments of mid-latitude Super Dual Auroral Radar Network (SuperDARN) HF radars

The Super Dual Auroral Radar Network (SuperDARN) is a network of high-frequency (HF) radars located in the high- and mid-latitude regions of both hemispheres that is operated under international cooperation. The network was originally designed for monitoring the dynamics of the ionosphere and upper atmosphere in the high-latitude regions. However, over the last approximately 15 years, SuperDARN has expanded into the mid-latitude regions. With radar coverage that now extends continuously from auroral to sub-auroral and mid-latitudes, a wide variety of new scientific findings have been obtained. In this paper, the background of mid-latitude SuperDARN is presented at first. Then, the accomplishments made with mid-latitude SuperDARN radars are reviewed in five specified scientific and technical areas: convection, ionospheric irregularities, HF propagation analysis, ion-neutral interactions, and magnetohydrodynamic (MHD) waves. Finally, the present status of mid-latitude SuperDARN is updated and directions for future research are discussed.

Nishitani, Nozomu; Ruohoniemi, John; Lester, Mark; Baker, Joseph; Koustov, Alexandre; Shepherd, Simon; Chisham, Gareth; Hori, Tomoaki; Thomas, Evan; Makarevich, Roman; , others;

Published by: Progress in Earth and Planetary Science      Published on:

YEAR: 2019     DOI: 10.1186/s40645-019-0270-5

Topside ionospheric conditions during the 7—8 September 2017 geomagnetic storm

The uplooking total electron contents (TECs) from the GRACE, SWARM-A, TerraSAR-X, and MetOp-A satellites and in situ electron density (Ne) from SWARM-A were utilized to investigate the topside ionospheric conditions during the 7–8 September 2017 geomagnetic storm. The rate of TEC index (ROTI) and rate of density index (RODI), which are derivative indices of TEC and Ne, respectively, were also used to characterize the topside ionospheric irregularities. The main results of this study are as follows: (1) There were significant enhancements seen in the uplooking TEC during the first main phase of the storm. (2) The uplooking TEC did not show unusual enhancement at the morning and evening local times in the Asian-Australian sector during the recovery phase of the storm. (3) Prominent TEC hemispheric asymmetry at the middle and high latitudes was observed at both day and night sectors. (4) Long-duration recovery of topside TEC with respect to the prestorm condition was also detected in this event. (5) Nighttime ROTI enhancements were presented in a wide latitudinal range from the equator to the poles during the main phases of the storm. (6) The ionospheric electric field disturbances associated with IMF-Bz fluctuations probably played a very important role in triggering ionospheric irregularities during the relatively weak geomagnetic activity on 7 September, which implies that ionospheric irregularities do not necessarily occur under the severe geomagnetic conditions only.

Jimoh, Oluwaseyi; Lei, Jiuhou; Zhong, Jiahao; Owolabi, Charles; Luan, Xiaoli; Dou, Xiankang;

Published by: Journal of Geophysical Research: Space Physics      Published on:

YEAR: 2019     DOI: 10.1029/2019JA026590

Space Weather Program at Antarctica

The use of GPS (Global Positioning System) in diverse areas such as surveying, enroute navigation and precision approach of aircraft, deformation monitoring, and various land/marine navigation applications necessitate high accuracy and availability. In the presence of time varying irregularities in ionospheric degrades the performance of the GPS receiver.

Tiwari, R; Purohit, PK; Gwal, AK;

Published by:       Published on:

YEAR: 2019     DOI:

Driving of strong nightside reconnection and geomagnetic activity by polar cap flows: application to CME shocks and possibly other situations

Lyons, LR; Gallardo-Lacourt, B; Zou, Y; Nishimura, Y; Anderson, P; , Angelopoulos; Donovan, EF; Ruohoniemi, JM; Mitchell, E; Paxton, LJ; , others;

Published by: Journal of Atmospheric and Solar-Terrestrial Physics      Published on:

YEAR: 2018     DOI:

The JHU APL Commercial Launch Program: JANUS is finally getting off the ground

Smith, Howard; Hacala, Ryan; Hohlfeld, Erik; Edens, Wes; Paxton, Larry; Hibbitts, Charles; Arnold, Steven;

Published by:       Published on:

YEAR: 2018     DOI:

The 2018 Parker Solar/Heliophysics Lecture

Paxton, Larry; Cohen, Christina;

Published by:       Published on:

YEAR: 2018     DOI:

The effect of ring current electron scattering rates on magnetosphere-ionosphere coupling

This simulation study investigated the electrodynamic impact of varying descriptions of the diffuse aurora on the magnetosphere-ionosphere (M-I) system. Pitch angle diffusion caused by waves in the inner magnetosphere is the primary source term for the diffuse aurora, especially during storm time. The magnetic local time (MLT) and storm-dependent electrodynamic impacts of the diffuse aurora were analyzed using a comparison between a new self-consistent version of the Hot Electron Ion Drift Integrator with varying electron scattering rates and real geomagnetic storm events. The results were compared with Dst and hemispheric power indices, as well as auroral electron flux and cross-track plasma velocity observations. It was found that changing the maximum lifetime of electrons in the ring current by 2\textendash6\ h can alter electric fields in the nightside ionosphere by up to 26\%. The lifetime also strongly influenced the location of the aurora, but the model generally produced aurora equatorward of observations.

Perlongo, N.; Ridley, A.; Liemohn, M.; Katus, R.;

Published by: Journal of Geophysical Research: Space Physics      Published on: 04/2017

YEAR: 2017     DOI: 10.1002/2016JA023679

Driving of Dramatic Geomagnetic Activity by Enhancement of Meso-Scale Polar-cap Flows

Lyons, Larry; Gallardo-Lacourt, Bea; Zou, Ying; Nishimura, Yukitoshi; Anderson, Phillip; Angelopoulos, VASSILIS; Ruohoniemi, Michael; Mitchell, Elizabeth; Paxton, Larry; Nishitani, Nozomu;

Published by:       Published on:

YEAR: 2017     DOI:

The 2017 Van Allen Lecture

Paxton, Larry; Cohen, Christina;

Published by:       Published on:

YEAR: 2017     DOI:

Ionospheric Space Weather: Longitude Dependence and Lower Atmosphere Forcing

This monograph is the outcome of an American Geophysical Union Chapman Conference on longitude and hemispheric dependence of ionospheric space weather, including the

Fuller-Rowell, Timothy; Yizengaw, Endawoke; Doherty, Patricia; Basu, Sunanda;

Published by:       Published on:

YEAR: 2016     DOI:

GPS phase scintillation at high latitudes during two geomagnetic storms

Prikryl, Paul; Ghoddousi-Fard, Reza; Ruohoniemi, John; Thomas, Evan; Zhang, Y; Paxton, LJ;

Published by: Auroral dynamics and space weather      Published on:

YEAR: 2015     DOI:

Investigation of sudden electron density depletions observed in the dusk sector by the Poker Flat, Alaska incoherent scatter radar in summer

This paper investigates unusually deep and sudden electron density depletions (troughs) observed in the Poker Flat (Alaska) Incoherent Scatter Radar data in middle summer of 2007 and 2008. The troughs were observed in the premidnight sector during periods of weak magnetic and solar activity. The density recovered to normal levels around midnight. At the time when the electron density was undergoing its steep decrease, there was usually a surge of the order of 100 to 400 K in the ion temperature that lasted less than 1 h. The Ti surges were usually related to similar surges in the AE index, indicating that the high-latitude convection pattern was expanding and intensifying at the time of the steep electron density drop. The convection patterns from the Super Dual Auroral Radar Network also indicate that the density troughs were associated with the expansion of the convection pattern to Poker Flat. The sudden decreases in the electron density are difficult to explain in summer because the high-latitude region remains sunlit for most of the day. This paper suggests that the summer density troughs result from lower latitude plasma that had initially been corotating in darkness for several hours post sunset and brought back toward the sunlit side as the convection pattern expanded. The magnetic declination of ~22\textdegree east at 300 km at Poker Flat greatly facilitates the contrast between the plasma convecting from lower latitudes and the plasma that follows the high-latitude convection pattern.

Richards, P.; Nicolls, M.; St.-Maurice, J.-P.; Goodwin, L.; Ruohoniemi, J.;

Published by: Journal of Geophysical Research: Space Physics      Published on: 12/2014

YEAR: 2014     DOI: 10.1002/jgra.v119.1210.1002/2014JA020541

ion temperature; plasma convection; plasma troughs

Solar filament impact on 21 January 2005: Geospace consequences

On 21 January 2005, a moderate magnetic storm produced a number of anomalous features, some seen more typically during superstorms. The aim of this study is to establish the differences in the space environment from what we expect (and normally observe) for a storm of this intensity, which make it behave in some ways like a superstorm. The storm was driven by one of the fastest interplanetary coronal mass ejections in solar cycle 23, containing a piece of the dense erupting solar filament material. The momentum of the massive solar filament caused it to push its way through the flux rope as the interplanetary coronal mass ejection decelerated moving toward 1 AU creating the appearance of an eroded flux rope (see companion paper by Manchester et al. (2014)) and, in this case, limiting the intensity of the resulting geomagnetic storm. On impact, the solar filament further disrupted the partial ring current shielding in existence at the time, creating a brief superfountain in the equatorial ionosphere\textemdashan unusual occurrence for a moderate storm. Within 1 h after impact, a cold dense plasma sheet (CDPS) formed out of the filament material. As the interplanetary magnetic field (IMF) rotated from obliquely to more purely northward, the magnetotail transformed from an open to a closed configuration and the CDPS evolved from warmer to cooler temperatures. Plasma sheet densities reached tens per cubic centimeter along the flanks\textemdashhigh enough to inflate the magnetotail in the simulation under northward IMF conditions despite the cool temperatures. Observational evidence for this stretching was provided by a corresponding expansion and intensification of both the auroral oval and ring current precipitation zones linked to magnetotail stretching by field line curvature scattering. Strong Joule heating in the cusps, a by-product of the CDPS formation process, contributed to an equatorward neutral wind surge that reached low latitudes within 1\textendash2 h and intensified the equatorial ionization anomaly. Understanding the geospace consequences of extremes in density and pressure is important because some of the largest and most damaging space weather events ever observed contained similar intervals of dense solar material.

Kozyra, J.; Liemohn, M.; Cattell, C.; De Zeeuw, D.; Escoubet, C.; Evans, D.; Fang, X.; Fok, M.-C.; Frey, H.; Gonzalez, W.; Hairston, M.; Heelis, R.; Lu, G.; Manchester, W.; Mende, S.; Paxton, L.; Rastaetter, L.; Ridley, A.; Sandanger, M.; Soraas, F.; Sotirelis, T.; Thomsen, M.; Tsurutani, B.; Verkhoglyadova, O.;

Published by: Journal of Geophysical Research: Space Physics      Published on: 07/2014

YEAR: 2014     DOI: 10.1002/2013JA019748

cold dense plasma sheet; Equatorial anomaly; magnetotail; precipitation; prompt penetration electric field; solar filament

Is Space Weather Different Over Africa, and If So, Why? An AGU Chapman Conference Report

With the increasing reliance on technology, the impact of space weather on engineered systems will certainly increase unless suitable protective measures are taken. Understanding the physics behind space weather impacts and improving the forecasting are the major objectives of the space science community. It is well recognized that many space weather impacts, especially on communications systems, arise from structures in the ionosphere. The equatorial ionosphere, in particular, is one of the most complex and is host to numerous instabilities and interactions, with many unresolved questions regarding its dynamics and variability. Radio waves, either transmitted through the ionosphere, for satellite communication and navigation, or reflected off the ionosphere for HF and radar applications, are all impacted by ionospheric variability and structure. Ionospheric irregularities or plasma \textquotedblleftbubbles\textquotedblright occurring at low latitudes are one such source of interference. These irregularities cause scintillations on satellite radio transmissions, resulting in information loss in communications, as well as degradation in positioning and navigation used in aviation and maritime industries.

Yizengaw, Endawoke; Doherty, Patricia; Fuller-Rowell, Tim;

Published by: Space Weather      Published on: 07/2013

YEAR: 2013     DOI: 10.1002/swe.20063

atmosphere ionosphere interactions; ionospheric irregularities; space weather

The Study of the origin of broad plasma depletions in the equatorial F region

Oh, S; Lee, W; Kil, H; Kwak, Y; Paxton, L; Zhang, Y;

Published by:       Published on:

YEAR: 2013     DOI:

Integral cross sections for the electron-impact excitation of the b 1 $\Pi$ u, c 3 1 $\Pi$ u, o 3 1 $\Pi$ u, b′ 1 $\Sigma$ u+, c 4′ 1 $\Sigma$ u+, G 3 $\Pi$ u, and F 3 $\Pi$ u states of N 2

Malone, Charles; Johnson, Paul; Liu, Xianming; Ajdari, Bahar; Kanik, Isik; Khakoo, Murtadha;

Published by: Physical Review A      Published on: 06/2012

YEAR: 2012     DOI: 10.1103/PhysRevA.85.062704

Reversed two-cell convection in the northern and southern hemisphere during northward IMF

Lu, G; Li, W; Raeder, J; Deng, Y; Rich, F; Ober, D; Zhang, Y; Paxton, L; Ruohoniemi, M; Hairston, M; , others;

Published by:       Published on:

YEAR: 2012     DOI:

Persistent longitudinal features in the low-latitude ionosphere

Kil, H; Lee, WK; Kwak, Y-S; Oh, S-J; Paxton, LJ; Zhang, Y;

Published by: Journal of Geophysical Research: Space Physics      Published on:

YEAR: 2012     DOI:

Reversed two-cell convection in the Northern and Southern hemispheres during northward interplanetary magnetic field

Lu, G.; Li, W.; Raeder, J.; Deng, Y.; Rich, F.; Ober, D.; Zhang, Y.; Paxton, L.; Ruohoniemi, J.; Hairston, M.; Newell, P.;

Published by: Journal of Geophysical Research      Published on: Jan-01-2011

YEAR: 2011     DOI: 10.1029/2011JA017043

The source of the longitudinal asymmetry in the ionospheric tidal structure

Kil, H.; Kwak, Y.-S.; Oh, S.-J.; Talaat, E.; Paxton, L.; Zhang, Y.;

Published by: Journal of Geophysical Research      Published on: Jan-01-2011

YEAR: 2011     DOI: 10.1029/2011JA016781

Temporal and spatial components in the storm-time ionospheric disturbances

Kil, Hyosub; Paxton, L.; Kim, Khan-Hyuk; Park, Sarah; Zhang, Yongliang; Oh, Seung-Jun;

Published by: Journal of Geophysical Research      Published on: Jan-01-2011

YEAR: 2011     DOI: 10.1029/2011JA016750

Longitudinal asymmetry in the crest intensity of the ionospheric tidal structure

Kil, H; Paxton, LJ; Zhang, Y; Kwak, Y; Oh, S;

Published by:       Published on:

YEAR: 2011     DOI:

Is DE2 the source of the ionospheric wave number 3 longitudinal structure?

Kil, H.; Paxton, L.; Lee, W.; Ren, Z.; Oh, S.-J.; Kwak, Y.-S.;

Published by: Journal of Geophysical Research      Published on: Jan-01-2010

YEAR: 2010     DOI: 10.1029/2010JA015979

The three dimensional characteristics of the equatorial plasma bubbles retrieved from TIMED/GUVI nightglow images

Oh, S; Kil, H; Paxton, LJ;

Published by:       Published on:

YEAR: 2010     DOI:

Global views of energetic particle precipitation and their sources: Combining large-scale models with observations during the 21-22 January 2005 magnetic storm

Kozyra, JU; Brandt, PC; Cattell, CA; Clilverd, M; de Zeeuw, D; Evans, DS; Fang, X; Frey, HU; Kavanagh, AJ; Liemohn, MW; , others;

Published by:       Published on:

YEAR: 2010     DOI:

Formation of a plasma depletion shell in the equatorial ionosphere

An accurate description of the irregularity region defined by a plasma bubble is critically important in understanding the dynamics of the region and its effects on radio scintillation. Here we describe a plasma depletion region as a \textquotedblleftdepletion shell\textquotedblright and show how two-dimensional optical images from space can be used to define the shape of the depletion shell. Our simple model calculation demonstrates that the space-based optical observation can detect the plasma-depleted magnetic flux tubes only near the F-peak height. The backward C-shape in bubble images from optical observations is the trace of the plasma depletion shell near the F-peak height. The westward tilt of bubbles at the magnetic equator can also be explained by this shell structure. The in situ measurement of the ion velocity at night in the topside shows the decrease of the eastward plasma drift with an increase of latitude. The formation of the plasma depletion shell is consistent with the latitudinal/altitudinal shear in the zonal plasma flow.

Kil, Hyosub; Heelis, Roderick; Paxton, Larry; Oh, Seung-Jun;

Published by: Journal of Geophysical Research      Published on: 11/2009

YEAR: 2009     DOI: 10.1029/2009JA014369

Equatorial ionosphere; plasma depletion shell; zonal shear flow

The Variability of the Zonal Plasma Drift in the Equatorial F Region

Kil, H; Kang, C; Oh, S; Kwak, Y; Lee, W; Paxton, LJ;

Published by:       Published on:

YEAR: 2009     DOI:

The One-to-one Comparison of the Pre-reversal Enhancement Characteristics with the Equatorial Plasma Bubble Occurrence using Multiple Satellite Data

Oh, SJ; Kil, H; Kim, YH;

Published by: Bulletin of the Korean Space Science Society      Published on:

YEAR: 2009     DOI:

Putting Space Physics Data Facility (SPDF) Services to Good Use

Candey, RM; Bilitza, D; Chimiak, R; Cooper, JF; Garcia, LN; Harris, B; Johnson, RC; King, JH; Kovalick, T; Leckner, H; , others;

Published by:       Published on:

YEAR: 2009     DOI:

The day-to-day variability of the occurrence of equatorial plasma bubbles

Oh, Seung; Kil, Hyosub; Paxton, Larry; Kim, Yong;

Published by:       Published on:

YEAR: 2009     DOI:

LONGITUDINAL VARIATION OF THE ANNUAL AND HEMISPHERIC ASYMMETRIES OF THE LOW-MIDDLE LATITUDE IONOSPHERE

Kwak, Y; Kil, H; Oh, S; Lee, W; Forbes, JM; Cho, K;

Published by:       Published on:

YEAR: 2009     DOI:

The causal link of the DE-3 tide, vertical drift, and plasma density

Kil, Hyosub; Talaat, Elsayed; Paxton, Larry; Fang, Tzu-Wei; Oh, Seung-Jun;

Published by:       Published on:

YEAR: 2009     DOI:

The solar cycle dependence variability of the occurrence pattern of the equatorial plasma bubbles retrieved from TIMED/GUVI nightglow images

Oh, S; Kil, H; Paxton, LJ; Kim, Y;

Published by:       Published on:

YEAR: 2009     DOI:

Are Unusual Solar Wind Conditions in SC23-24 Triggering Changes in the Geospace Response to High Speed Streams?

In the descent to solar minimum in solar cycle 23-24, the high-speed streams (HSS) were faster and longer lived than previous cycles but the average IMF was weaker and the average solar wind density lower than ever before recorded upstream of the Earth. A simulation of high speed stream activity on 22-24 January 2005 using the BATS-R-US MHD model with embedded Rice Convection Model driven by solar wind inputs indicates that, at least for this event, the interaction between high speed streams and the magnetosphere has been modified by these unusual solar wind conditions. Northward IMF in the HSS drove the periodic capture of solar wind/magnetosheath plasma in the dayside magnetosphere due to high-latitude reconnection. At times of observed strong periodic auroral activity, a significant IMF By component produced a magnetospheric sash configuration in the simulations in which fingers of enhanced plasma beta were associated with strong field-aligned currents linking to the nightside auroral region. In agreement with the simulations, IMAGE HENA observed low energy (less than tens of keV) hydrogen energetic neutral atoms peaking on the dayside for the 3-days of the high speed stream activity. IMAGE FUV and TIMED GUVI observed periodic auroral activations during the HSS that resembled poleward boundary intensifications (PBIs) rather than the periodic substorms typically associated with HSS. The locations of the observed PBIs in the southern hemisphere were consistent with the high-beta fingers in the near-Earth plasma sheet predicted by the simulation. Particle injection signatures at LANL geosynchronous satellites accompanied the PBIs. To our knowledge, these results provide the first evidence in support of the role of northward IMF in HSS interactions. Based on these results, a study of energetic neutral atom images from TWINS and IMAGE HENA along with observations from other missions in the Heliophysics System Observatory is underway to determine if these characteristics are typical of HSS interactions in the current unusual solar minimum and to search for consequences throughout geospace.

Kozyra, JU; Brandt, PC; Buzulukova, N; de Zeeuw, D; Fok, MH; Frey, HU; Gibson, SE; Ilie, R; Liemohn, MW; Mende, SB; , others;

Published by:       Published on:

YEAR: 2009     DOI:

Global bubble distribution seen from ROCSAT-1 and its association with the evening prereversal enhancement

Kil, Hyosub; Paxton, Larry; Oh, Seung-Jun;

Published by: Journal of Geophysical Research: Space Physics      Published on:

YEAR: 2009     DOI: 10.1029/2008JA013672

Wave structures of the plasma density and vertical E$\times$ B drift in low-latitude F region

We investigate the seasonal, longitudinal, local time (LT), and altitudinal variations of the F region morphology at low latitudes using data from the first Republic of China satellite (ROCSAT-1), Global Ultraviolet Imager (GUVI), on board the Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) satellite, and the Defense Meteorological Satellite Program (DMSP) F13 and F15 satellites. Signatures of the longitudinally periodic plasma density structure emerge before 0900 LT. The wave structure is established before noon and further amplified in the afternoon. The amplitudes of the wave structure start to diminish in the evening. The wave-4 structure is clearly distinguishable during equinox and northern hemisphere summer. During northern hemisphere winter, the density structure can be characterized to either wave-4 or wave-3 structure owing to marginal separation of the two peaks in 180°–300°E. Observations of similar density structures from ROCSAT-1 (600 km) and DMSP (840 km) at 0930 and 1800 LT indicate the extension of the wave structure to altitudes greater than 840 km. The daytime wave structure persists into the night during the equinoxes but is significantly modified during the solstices. The modification is more significant at higher altitudes and is attributed to the effects of interhemispheric winds and the prereversal enhancement. The formation of the wavelike density structure in the morning and its temporal evolution in the afternoon show a close association with the vertical E × B drift. We conclude that the E × B drift during 0900–1200 LT determines the formation of the wavelike density structure.

Kil, H.; Talaat, E.; Oh, S.-J.; Paxton, L.; England, S.; Su, S.-Y.;

Published by: Journal of Geophysical Research      Published on: Jan-01-2008

YEAR: 2008     DOI: 10.1029/2008JA013106

Equatorial ionosphere; wave structure; atmospheric tide

The effect of the vertical $ E $\$$\backslash$times$\$ B $ drift on the formation of the longitudinal plasma density structure in the low-latitude F-region

Oh, SJ; Kil, H; Kim, W; Paxton, LJ; Kim, YH;

Published by: Bulletin of the Korean Space Science Society      Published on:

YEAR: 2008     DOI:

Wave structures of the plasma density and vertical E$\times$ B drift in low-latitude F region

Kil, H; Talaat, ER; Oh, S-J; Paxton, LJ; England, SL; Su, S-Y;

Published by: Journal of Geophysical Research: Space Physics      Published on:

YEAR: 2008     DOI:

The role of the vertical E$\times$ B drift for the formation of the longitudinal plasma density structure in the low-latitude F region

Oh, S-J; Kil, H; Kim, W-T; Paxton, LJ; Kim, YH;

Published by:       Published on:

YEAR: 2008     DOI:

The temporal variability of the longitudinal plasma density structure in the low-latitude F-region

Oh, SJ; Kil, H; Kim, YH;

Published by: Bulletin of the Korean Space Science Society      Published on:

YEAR: 2008     DOI:

Abnormal vertical drifts of equatorial plasma before dawn and after sunset during the storm of 29—30 October 2003

Kil, Hyosub; Oh, Seung-Jun; Paxton, Larry;

Published by: Geophysical research letters      Published on:

YEAR: 2008     DOI:

Retrieval of 3-D equatorial plasma bubble characteristics from the TIMED/GUVI nightglow images.

Oh, SJ; Kil, H;

Published by:       Published on:

YEAR: 2008     DOI:

Observations of ionospheric convection from the Wallops SuperDARN radar at middle latitudes

Baker, J.; Greenwald, R.; Ruohoniemi, J.; Oksavik, K.; Gjerloev, J.; Paxton, L.; Hairston, M.;

Published by: Journal of Geophysical Research      Published on: Jan-01-2007

YEAR: 2007     DOI: 10.1029/2006JA011982

Retrieval of 2-D equatorial plasma bubble images from the TIMED/GUVI data

Oh, SJ; Kil, H;

Published by:       Published on:

YEAR: 2007     DOI: