Bibliography

Echo occurrence in the southern polar ionosphere for the SuperDARN Dome C East and Dome C North radars

In this paper, echo occurrence rates for the Dome C East (DCE) and the new Dome C North (DCN) radars are studied. We report the ionospheric and ground scatter echo occurrence rates for selected periods around equinoxes and solstices in the final part of the solar cycle XXIV. The occurrence maps built in Altitude Adjusted Corrected Geomagnetic latitude and Magnetic Local Time coordinates show peculiar patterns highly variable with season. The comparisons of the radar observations with the International Reference Ionosphere model electron density and with ray tracing simulations allow us to explain the major features of observed patterns in terms of electron density variations. The study shows the great potential of the DCE and DCN radar combination to the Super Dual Auroral Radar Network (SuperDARN) convection mapping in terms of monitoring key regions of the high-latitude ionosphere critical for understanding of the magnetospheric dynamics.

Marcucci, Maria; Coco, Igino; Massetti, Stefano; Pignalberi, Alessio; Forsythe, Victoriya; Pezzopane, Michael; Koustov, Alexander; Longo, Simona; Biondi, David; Simeoli, Enrico; Consolini, Giuseppe; Laurenza, Monica; Marchaudon, Aurélie; Satta, Andrea; Cirioni, Alessandro; De Simone, Angelo; Olivieri, Angelo; Baù, Alessandro; Salvati, Alberto;

Published by: Polar Science      Published on: jun

YEAR: 2021     DOI: 10.1016/j.polar.2021.100684

Echo occurrence; IRI model; Polar cap radars; Ray-tracing

An Unusually Large Electron Temperature Increase Over Arecibo Associated With an Intense Geomagnetic Storm

We present an investigation of the F-region electron temperature to an intense geomagnetic storm that occurred on 5 August 2011. The investigation is based on the incoherent scatter radar measurements at Arecibo Observatory, Puerto Rico (18.3°N, 66.7°W). The electron temperature exhibits a rapid and intensive enhancement after the commencement of the geomagnetic storm. The electron temperature increases by ∼800 K within an hour, which is seldomly reported at Arecibo. At the same time, a depletion of the electron density is also observed. The daytime perturbations of electron density and temperature are anticorrelated with the correlation coefficient, which is −0.88 and −0.91 on the day and the following day of the geomagnetic storm, respectively. According to the Global Ultraviolet Imager measurements, the ratio of atomic oxygen to molecular nitrogen concentration () decreases dramatically during the storm. Our analysis suggests that the enhancement of the electron temperature is due to the depletion of the electron density, which is likely associated with the decrease of . The reduction of maybe caused by a prompt upward plasma motion after the commencement of the geomagnetic storm.

Lv, Xiedong; Gong, Yun; Zhang, ShaoDong; Zhou, Qihou; Ma, Zheng;

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

YEAR: 2021     DOI: 10.1029/2021JA029836

Arecibo; F-region electron temperature; geomagnetic storm; incoherent scatter radar

First Look at a Geomagnetic Storm With Santa Maria Digisonde Data: F Region Responses and Comparisons Over the American Sector

Santa Maria Digisonde data are used for the first time to investigate the F region behavior during a geomagnetic storm. The August 25, 2018 storm is considered complex due to the incidence of two Interplanetary Coronal Mass Ejections and a High-Speed Solar Wind Stream (HSS). The F 2 layer critical frequency (f o F 2) and its peak height (h m F 2) collected over Santa Maria, near the center of the South American Magnetic Anomaly (SAMA), are compared with data collected from Digisondes installed in the Northern (NH) and Southern (SH) Hemispheres in the American sector. The deviation of f o F 2 (Df o F 2) and h m F 2 (Dh m F 2) are used to quantify the ionospheric storm effects. Different F region responses were observed during the main phase (August 25–26), which is attributed to the traveling ionospheric disturbances and disturbed eastward electric field during nighttime. The F region responses became highly asymmetric between the NH and SH at the early recovery phase (RP, August 26) due to a combination of physical mechanisms. The observed asymmetries are interpreted as caused by modifications in the thermospheric composition and a rapid electrodynamic mechanism. The persistent enhanced thermospheric [O]/[N2] ratio observed from August 27 to 29 combined with the increased solar wind speed induced by the HSS and IMF B z fluctuations seem to be effective in causing the positive ionospheric storm effects and the shift of the Equatorial Ionization Anomaly crest to higher than typical latitudes. Consequently, the most dramatic positive ionospheric storm during the RP occurred over Santa Maria (∼120\%).

Moro, J.; Xu, J.; Denardini, C.; Resende, L.; Neto, P.; Da Silva, L.; Silva, R.; Chen, S.; Picanço, G.; Carmo, C.; Liu, Z.; Yan, C.; Wang, C.; Schuch, N.;

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

YEAR: 2021     DOI: 10.1029/2020JA028663

Digisonde; Equatorial ionization anomaly; F-region; Ionospheric storm; SAMA; space weather

First Look at a Geomagnetic Storm With Santa Maria Digisonde Data: F Region Responses and Comparisons Over the American Sector

Santa Maria Digisonde data are used for the first time to investigate the F region behavior during a geomagnetic storm. The August 25, 2018 storm is considered complex due to the incidence of two Interplanetary Coronal Mass Ejections and a High-Speed Solar Wind Stream (HSS). The F 2 layer critical frequency (f o F 2) and its peak height (h m F 2) collected over Santa Maria, near the center of the South American Magnetic Anomaly (SAMA), are compared with data collected from Digisondes installed in the Northern (NH) and Southern (SH) Hemispheres in the American sector. The deviation of f o F 2 (Df o F 2) and h m F 2 (Dh m F 2) are used to quantify the ionospheric storm effects. Different F region responses were observed during the main phase (August 25–26), which is attributed to the traveling ionospheric disturbances and disturbed eastward electric field during nighttime. The F region responses became highly asymmetric between the NH and SH at the early recovery phase (RP, August 26) due to a combination of physical mechanisms. The observed asymmetries are interpreted as caused by modifications in the thermospheric composition and a rapid electrodynamic mechanism. The persistent enhanced thermospheric [O]/[N2] ratio observed from August 27 to 29 combined with the increased solar wind speed induced by the HSS and IMF B z fluctuations seem to be effective in causing the positive ionospheric storm effects and the shift of the Equatorial Ionization Anomaly crest to higher than typical latitudes. Consequently, the most dramatic positive ionospheric storm during the RP occurred over Santa Maria (∼120\%).

Moro, J.; Xu, J.; Denardini, C.; Resende, L.; Neto, P.; Da Silva, L.; Silva, R.; Chen, S.; Picanço, G.; Carmo, C.; Liu, Z.; Yan, C.; Wang, C.; Schuch, N.;

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

YEAR: 2021     DOI: 10.1029/2020JA028663

Digisonde; Equatorial ionization anomaly; F-region; Ionospheric storm; SAMA; space weather

Far Ultraviolet Hyperspectral Imager: NASA's TIMED/GUVI and DMSP SSUSI

Paxton, Larry; Zhang, Yongliang; Schaefer, Robert; Kil, Hyosub; Wolven, Brian; Romeo, Giuseppe; Yonker, Justin;

Published by:       Published on:

YEAR: 2021     DOI:

Large Electron Densities in the Early Morning Equatorial Ionosphere Observed with UV Instruments from Space

Schaefer, Robert; Paxton, Larry; Zhang, Yongliang; Kil, Hyosub; Romeo, Giuseppe; Wolven, Brian; Yonker, Justin;

Published by:       Published on:

YEAR: 2021     DOI:

Statistical Analysis of Throat Aurora Using Long Term DMSP/SSUSI Observation

Throat aurora is believed to be associated with magnetopause indentations and has direct implications on magnetopause reconnection. In this study, for the first time, we use Defense Meteorological Satellite Program/Special Sensor Ultraviolet Spectrographic Imager observations over ∼14 years to characterize the throat aurora occurrence, latitudinal extent, seasonal, and its solar cycle dependence. We identified 386 throat aurora cases during the different passes of the satellite over the northern hemisphere. The latitudinal extent of these throat aurorae are estimated and are divided into small, medium, and large categories. The small and medium latitudinal extent throat aurorae account for about 91\% of the total cases. The throat aurorae are found to occur most frequently in the post-noon hours. The throat aurorae were also observed more frequently during winter, likely due to summer-winter asymmetry in the ionospheric conductance. The occurrence of the throat aurora is also found to be anti-correlated with the solar cycle, likely because low solar activity gives good chances for sporadic reconnection that favors the occurrence of throat aurora. The dependence on interplanetary magnetic field reveals positive Bx favoring the occurrence of throat aurora. It also shows positive Bx (negative By) supports pre-noon (post-noon) occurrence. The difference in the trend and average values of background interplanetary magnetic field conditions with the throat aurora confirms the favorable conditions for the occurrence of throat aurora.

Selvakumaran, R.; Han, De-Sheng; Gokani, Sneha; Zhang, Y.;

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

YEAR: 2021     DOI: 10.1029/2021JA029164

auroral oval; magnetopause indentations; throat aurora

Addressing O2R with the SSUSI Operational Space Sensor: Lessons Learned

Schaefer, Robert; Paxton, Larry; Romeo, Giuseppe; Kil, Hyosub; Wolven, Brian; Zhang, Yongliang;

Published by:       Published on:

YEAR: 2019     DOI:

A New More Accurate Calibration for TIMED/GUVI

Schaefer, RK; Aiello, J; Wolven, BC; Paxton, LJ; Romeo, G; Zhang, Y;

Published by:       Published on:

YEAR: 2017     DOI:

Observation and Modeling of the South Atlantic Anomaly in Low Earth Orbit Using Photometric Instrument Data

Selby, Christina; Paxton, LJ; Schaefer, RK; Ogorzalek, B; Romeo, G; Wolven, B; Hsieh, SY;

Published by:       Published on:

YEAR: 2016     DOI:

Remote sensing of Earth's limb by TIMED/GUVI: Retrieval of thermospheric composition and temperature

The Global Ultraviolet Imager (GUVI) onboard the Thermosphere-Ionosphere-Mesosphere Energetics and Dynamics (TIMED) satellite senses far ultraviolet emissions from O and N₂ in the thermosphere. Transformation of far ultraviolet radiances measured on the Earth limb into O, N₂, and O₂ number densities and temperature quantifies these responses and demonstrates the value of simultaneous altitude and geographic information. Composition and temperature variations are available from 2002 to 2007. This paper documents the extraction of these data products from the limb emission rates. We present the characteristics of the GUVI limb observations, retrievals of thermospheric neutral composition and temperature from the forward model, and the dramatic changes of the thermosphere with the solar cycle and geomagnetic activity. We examine the solar extreme ultraviolet (EUV) irradiance magnitude and trends through comparison with simultaneous Solar Extreme EUV (SEE) measurements on TIMED and find the EUV irradiance inferred from GUVI averaged (2002\textendash2007) 30\% lower magnitude than SEE version 11 and varied less with solar activity. The smaller GUVI variability is not consistent with the view that lower solar EUV radiation during the past solar minimum is the cause of historically low thermospheric mass densities. Thermospheric O and N₂ densities are lower than the NRLMSISE-00 model, but O₂ is consistent. We list some lessons learned from the GUVI program along with several unresolved issues.

Meier, R.; Picone, J.; Drob, D.; Bishop, J.; Emmert, J.; Lean, J.; Stephan, A.; Strickland, D.; Christensen, A.; Paxton, L.; Morrison, D.; Kil, H.; Wolven, B.; Woods, Thomas; Crowley, G.; Gibson, S.;

Published by: Earth and Space Science      Published on: 01/2015

YEAR: 2015     DOI: 10.1002/2014EA000035

airglow and aurora; remote sensing; thermosphere: composition and chemistry; thermosphere: energy deposition

UV Observations of Hemispheric Asymmetry

Schaefer, Robert; Paxton, Larry; Wolven, Brian; Zhang, Yongliang; Romeo, Giuseppe;

Published by:       Published on:

YEAR: 2015     DOI:

Updated Global Data from the Guvi Instrument: New Products, Updated Calibration, and a New Web Interface

Schaefer, Robert; Paxton, Larry; Romeo, Giuseppe; Wolven, Brian; Zhang, Yongliang; Comberiate, Joseph;

Published by:       Published on:

YEAR: 2014     DOI:

Multi-Instrument Observations at High Latitudes

Miller, E; Paxton, L; Schaefer, RK; Weiss, M; Wolven, BC; Zhang, Y;

Published by:       Published on:

YEAR: 2013     DOI:

Observing the Edge of the Inner Radiation Belt: the South Atlantic Anomaly Seen with Photometers in Low Earth Orbit

Schaefer, RK; Wolven, BC; Paxton, L; Romeo, G; Selby, C; Hsieh, SW;

Published by:       Published on:

YEAR: 2013     DOI:

Global propagation of gravity waves generated with the whole atmosphere transfer function model

Mayr, Hans; Talaat, Elsayed; Wolven, Brian;

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

YEAR: 2013     DOI:

UV Remote Sensing Data Products-Turning Data Into Knowledge

Weiss, M; Paxton, L; Schaefer, RK; Comberiate, J; Hsieh, SW; Romeo, G; Wolven, BC; Zhang, Y;

Published by:       Published on:

YEAR: 2013     DOI:

SSUSI: A Newly Available Resource for the Upper Atmosphere Community to Study the Global Response of the Coupled Ionosphere Thermosphere System

Paxton, L; Schaefer, RK; Weiss, M; Wolven, BC; Zhang, Y; Miller, E; Bust, GS; Romeo, G;

Published by:       Published on:

YEAR: 2013     DOI:

Space Weather Products from UV Imagers in Low Earth Orbit-Providing Key Information about the ITM Environment

Romeo, G; Paxton, LJ; Schaefer, RK; DeMajistre, R; Comberiate, J; Hsieh, SW; Miller, ES; Weiss, M; Wolven, BC; Zhang, Y;

Published by:       Published on:

YEAR: 2012     DOI:

Ultraviolet Remote Sensing of Nitric Oxide in the Thermosphere Using the TIMED/GUVI Instrument

DeMajistre, R; Wolven, BC; Paxton, LJ; Zhang, Y; Schaefer, RK; Bailey, SM; Yonker, JD; Thurairajah, B;

Published by:       Published on:

YEAR: 2012     DOI:

New and Improved GUVI Data Products for ITM Research

Schaefer, RK; Paxton, LJ; DeMajistre, R; Comberiate, J; Hsieh, SW; Miller, ES; Romeo, G; Weiss, M; Wolven, BC; Zhang, Y;

Published by:       Published on:

YEAR: 2012     DOI:

Ten Years of GUVI Data: The Updated GUVI Far UV Data Archive

Wolven, B; Schaefer, R; Paxton, L; Holland, D; Zhang, Y; Christensen, A;

Published by:       Published on:

YEAR: 2011     DOI:

On the causes of plasmaspheric rotation variability: IMAGE EUV observations

Galvan, David; Moldwin, Mark; Sandel, Bill; Crowley, Geoff;

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

YEAR: 2010     DOI:

Enhanced UV Data Products-Observing the Ionosphere in Greater Fidelity

Wolven, BC; Paxton, LJ; Comberiate, J; Hsieh, SW; , Nylund; Schaefer, RK; Selby, C; Smith, D; Weiss, M; Zhang, Y;

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:

Global observations of the equatorial ionosphere by UV remote sensing

Paxton, Larry; Comberiate, Joseph; Kil, Hyosub; Schaefer, Robert; Wolven, Brian; Zhang, Yongliang; Morrison, Daniel;

Published by:       Published on:

YEAR: 2009     DOI:

Visualization and Analysis of Spectrograph-mode Data Products from Far Ultraviolet Scanning Imaging Sensors

Wolven, BC; Schaefer, RK; Hsieh, SW; Paxton, LJ;

Published by:       Published on:

YEAR: 2009     DOI:

Enhanced Global Coverage of the Thermosphere and Ionosphere: Adding New UV data (DMSP/SSUSI) to the TIMED/GUVI Database

Wolven, BC; Hsieh, S; Schaefer, RK;

Published by:       Published on:

YEAR: 2007     DOI:

Global inventory of precipitating populations during the 15-30 January 2005 long-duration flares and magnetic storms: Relative efficacy at ozone destruction

Kozyra, JU; Cattell, CA; Clilverd, M; Evans, DS; Kavanagh, A; Liemohn, MW; Mende, SB; Paxton, LJ; Ridley, A; Soraas, F;

Published by:       Published on:

YEAR: 2007     DOI:

TIMED/GUVI and DMSP/SSUSI-Data Products for Space Weather

Hsieh, S; Paxton, L; Zhang, Y; DeMajistre, R; Wolven, B; Morrison, D; Schaefer, R;

Published by:       Published on:

YEAR: 2006     DOI:

Observing the Coupled Ionosphere-Thermosphere System: From Solar Maximum to Solar Minimum and Beyond

Paxton, L; Morrison, D; Zhang, Y; Kil, H; Wolven, B; Comberiate, J; Meng, C; Kozyra, J; Christensen, A;

Published by:       Published on:

YEAR: 2006     DOI:

Analyses of solar activity effects on the low-latitude ionosphere

Wolven, BC; Talaat, ER; Yee, J; DeMajistre, R; Paxton, LJ; Christensen, A; Sotirelis, T; Smith, DC; Bilitza, D; Azeem, I;

Published by:       Published on:

YEAR: 2006     DOI:

GUVI Observations of Thermosphere/Ionosphere Coupling

Paxton, L; Zhang, Y; Kil, H; Morrison, D; Wolven, B; Meng, C; Christensen, A;

Published by:       Published on:

YEAR: 2006     DOI:

GUVI observations of the airglow response to solar flares: Results from the CAWSES campaign period

Wolven, BC; Paxton, LJ; Morrison, D;

Published by:       Published on:

YEAR: 2006     DOI:

Undulations on the equatorward edge of the diffuse proton aurora: TIMED/GUVI observations

Undulations on the equatorward edge of the diffuse proton aurora have been identified by using TIMED/GUVI auroral images in the far ultraviolet wavelengths. While undulations have been previously reported on the duskside (Lui et al., 1982), GUVI observations show the undulation also occurs in the dayside, nightside, and morningside. The GUVI proton auroral images provide direct optical evidence that the undulations occur in the proton aurora. It is also the first detection of the undulation in the dayside indicating strong convection shear in the region. The undulation in the nightside, a wavy structure in the whole diffuse proton aurora, is significantly different from those in the duskside and dayside. While almost all of the undulation events are observed during magnetic storms (Dst \< -60 nT), one exceptional case shows undulation in the dayside with Dst = 30 nT. However, the case is associated with a large solar wind speed (650 km/s) and a high dynamic pressure (14 nPa). Coincident DMSP SSIES observations suggest that both large ion drift velocity (\>1000 m/s) and strong velocity shear (\>0.1 s^-1) within the diffuse aurora oval are necessary conditions for the undulation to occur. The SSIES data also indicate the areas with large ion drift velocity and shear move to higher latitudes in the MLT sectors toward midnight. This may explain why the undulation is rarely detected in the nightside.

Zhang, Y.; Paxton, L.; Morrison, D.; T. Y. Lui, A.; Kil, H.; Wolven, B.; Meng, C.-I.; Christensen, A.;

Published by: Journal of Geophysical Research      Published on: 09/2005

YEAR: 2005     DOI: 10.1029/2004JA010668

auroral undulation; K-H instability; Magnetic storm; plasma convection

GUVI Observations of Solar EUV and Geomagnetic Storm Control of the Ionosphere and Thermosphere

Paxton, LJ; Yee, J; Zhang, Y; Kil, H; DeMajistre, R; Morrison, D; Wolven, B; Meng, C;

Published by:       Published on:

YEAR: 2005     DOI:

Integrated Solar Irradiance from 1-45 nm (Qeuv) as Determined from the GUVI instrument on TIMED

Morrison, D; Wolven, B; Paxton, L;

Published by:       Published on:

YEAR: 2005     DOI:

AURORA: The Next Generation Space Weather Sensor for NPOESS

Paxton, L; Morrison, D; Santo, A; Ogorzalek, B; Goldsten, J; Boldt, J; Kil, H; Zhang, Y; DeMajistre, R; Wolven, B; , others;

Published by:       Published on:

YEAR: 2005     DOI:

Auroral Undulations During Magnetic Storms: TIMED/GUVI Observations

Zhang, Y; Paxton, LJ; Morrison, D; Lui, T; Kil, H; Wolven, B; Meng, CI;

Published by:       Published on:

YEAR: 2005     DOI:

Hurricane-generated gravity waves as a trigger of ionospheric plasma instabilities

Wolven, BC; Paxton, LJ;

Published by:       Published on:

YEAR: 2005     DOI:

O/N2 morphology during quiet and moderate auroral activity and its relation to TEC

Zhang, Y; Paxton, LJ; Morrison, D; Kil, H; Wolven, B;

Published by:       Published on:

YEAR: 2005     DOI:

Far-ultraviolet signature of polar cusp during southward IMF Bz observed by TIMED/Global Ultraviolet Imager and DMSP

The coincident TIMED/Global Ultraviolet Imager (TIMED/GUVI) optical and DMSP particle observations have revealed new features of the optical signature of the polar cusp under a southward interplanetary magnetic field (IMF). We have found that cusp auroras usually take the shape of a thin arc with a width around 100\textendash200 km. This provides the first far-ultraviolet evidence of the narrow cusp under a southward IMF [Newell and Meng, 1987]. The cusp auroras could extend down to 0800 magnetic local time (MLT) in the morningside and 1400 MLT in the duskside. Its length is about a few thousand kilometers. A large solar wind density, speed, and IMF are necessary conditions for GUVI to observe the cusp aurora. We found that the cusp location at 1200 MLT changes linearly (-10 nT\ B_z\ \< 0 nT) and nonlinearly (B_z\ \< -10 nT) with the IMF\ B_z. The nonlinear effect can be explained by an\ L^-3\ dependence of the Earth\textquoterights equatorial magnetic field.

Zhang, Y; Meng, C-I; Paxton, LJ; Morrison, D; Wolven, B; Kil, H; Newell, P; Wing, S; Christensen, AB;

Published by: Journal of Geophysical Research: Space Physics (1978\textendash2012)      Published on:

YEAR: 2005     DOI: 10.1029/2004JA010707

cusp aurora

Imaging the Low-Latitude Ionosphere: Future Collaborations with C/NOFS

Paxton, L.; Kil, H.; DeMajistre, R.; Zhang, Y.; Morrison, D.; Wolven, B.; Meng, C.-I;

Published by:       Published on:

YEAR: 2005     DOI:

Nightside detached auroras due to precipitating protons/ions during intense magnetic storms

Nightside detached auroras (NDA) during intense magnetic storms are studied by using FUV image data from Thermosphere-Ionosphere-Mesosphere Energetics and Dynamics (TIMED)/Global Ultraviolet Imager (GUVI), Imager for Magnetopause-to-Aurora Global Exploration (IMAGE)/FUV, and particle data from DMSP/SSJ/4 instruments. We found that NDA are caused by proton/ion precipitation only. Thin arc-shaped NDA are very likely due to soft (\<1 keV) proton/ion precipitation. Thick or patch-shaped NDA are caused by energetic (\~10 keV) proton/ion precipitation. All the cases indicate that the NDA were observed when\ Dst\ was less -130 nT. More specifically, the NDA occurred during recovery or the lowest\ Dst\ period for each intense storm. The magnetic latitudes of the NDA are between 45\textdegree and 55\textdegree (Lshell: 2.0\textendash3.0). We found that the latitude location of the NDA is quasi-linearly correlated with\ Dst. The magnetic local time (MLT) of the NDA ranges from 1930 to 0300. All the facts indicate that the source of the NDA is the trapped protons/ions in the ring current. Precipitation of the trapped protons/ions is caused by an interaction between the perpendicularly heated ring current particles and the cold/dense plasma at the plasmapause.

Zhang, Y; Paxton, LJ; Morrison, D; Wolven, B; Kil, H; Wing, S;

Published by: Journal of Geophysical Research: Space Physics (1978\textendash2012)      Published on:

YEAR: 2005     DOI: 10.1029/2004JA010498

detached aurora; proton precipitation; ring current; Magnetic storm

TIMED/GUVI Observations of the Ionosphere and Thermosphere Interaction

Paxton, L.; Kil, H.; DeMajistre, R.; Zhang, Y.; Morrison, D.; Wolven, B.; Meng, C.-I.;

Published by: Ann. Geophys., special ISEA      Published on:

YEAR: 2005     DOI:

SSUSI and GUVI limb scans of thermospheric neutral density changes during a geomagnetic storm

Stephan, AW; Picone, JM; Meier, RR; Emmert, JT; Paxton, LJ; Morrison, D; Wolven, B; Kil, H;

Published by:       Published on:

YEAR: 2005     DOI:

Observations of solar and magnetospheric inputs and atmospheric responses to the January 2005 long duration flares and fast coronal mass ejections

Paxton, LJ; Kozyra, J; Demajistre, B; Kil, H; Morrison, D; Wolven, B; Mitchell, D; Brandt, P; Zhang, Y; Meng, C;

Published by:       Published on:

YEAR: 2005     DOI:

Coincident equatorial bubble detection by TIMED/GUVI and ROCSAT-1

Kil, Hyosub; Su, S.-Y.; Paxton, L.; Wolven, B.; Zhang, Y.; Morrison, D.; Yeh, H.;

Published by: Geophysical Research Letters      Published on: Jan-01-2004

YEAR: 2004     DOI: 10.1029/2003GL018696

O/N ₂ changes during 1--4 October 2002 storms: IMAGE SI-13 and TIMED/GUVI observations

Thermospheric O/N₂ column density ratios referenced at a N₂ column density of 10¹⁷ cm^-2 are obtained using the IMAGE SI-13 and TIMED/GUVI far-ultraviolet (FUV) dayglow data, AURIC simulation results, and MSIS86 model. Each of the magnetic storms occurring during a 4-day period (1\textendash4 October 2002) caused significant O/N₂ depletion that was detected by both of the IMAGE SI-13 and GUVI instruments. The depletion extended down to latitudes of 10\textdegree and -5\textdegree in the Northern and Southern Hemispheres, respectively. Simultaneous measurements show an excellent agreement between the SI-13 and GUVI O/N₂ on both global and local scales. The IMAGE SI-13 O/N₂ data provide direct optical evidence that the O/N₂ depletion corotates with the Earth. The GUVI O/N₂ indicate the depletion in both of the hemispheres is not symmetric owing to the seasonal effect and differences in heating and convection induced winds. Both the IMAGE SI-13 and GUVI O/N₂ maps also provide a good opportunity for future modeling efforts.

Zhang, Y.; Paxton, L.; Morrison, D.; Wolven, B.; Kil, H.; Meng, C.-I.; Mende, S.; Immel, T.;

Published by: Journal of Geophysical Research      Published on: 10/2004

YEAR: 2004     DOI: 10.1029/2004JA010441

Magnetic storm; thermospheric composition change

Double dayside detached auroras: TIMED/GUVI observations

On August 19, 2003, TIMED/GUVI detected, for the first time, two separated (double) dayside detached auroras (D-DDA) simultaneously in all the GUVI channels, 121.6 nm, 135.6 nm, LBHS, and LBHL. The D-DDA was located at magnetic latitudes around -57\textdegree and -63\textdegree (L shell 3.4 and 4.9) in the 0900\textendash1030 MLT region. The high-latitude part of the D-DDA is much brighter than the low-latitude part. DMSP particle observation indicates that the source of the D-DDA is energetic (\~10 keV) precipitating protons/electrons from the ring current due to the solar wind dynamic pressure enhancements [Zhang et al., 2002] and/or northward turning of the IMF B_z. Observations of the D-DDA provide the first single-event evidence of multiple peaks in the statistical distribution of proton fluxes at energetic around and below 10 keV at low L-shells [Milillo et al., 2001].

Zhang, Y.; Paxton, L.; Meng, C.-I.; Morrison, D.; Wolven, B.; Kil, H.; Christensen, A.;

Published by: Geophysical Research Letters      Published on: 05/2004

YEAR: 2004     DOI: 10.1029/2003GL018949