Bibliography

Neutral composition information in ICON EUV dayglow observations

Since the earliest space‐based observations of Earth s atmosphere, ultraviolet (UV) airglow has proven a useful resource for remote sensing of the ionosphere and thermosphere. The

Tuminello, Richard; England, Scott; Sirk, Martin; Meier, Robert; Stephan, Andrew; Korpela, Eric; Immel, Thomas; Mende, Stephen; Frey, Harald;

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

YEAR: 2022     DOI: 10.1029/2022JA030592

Time Delay Integration Imaging of the Nighttime Ionosphere from the ICON Observatory

TIMED GUVI was on a high inclination orbit changing local time relatively slowly and missing a great deal of the equatorward low latitude regions at the wrong local times.

Mende, SB; Frey, HU; England, SL; Immel, TJ; Eastes, RW;

Published by: Space Science Reviews      Published on:

YEAR: 2022     DOI: 10.1007/s11214-022-00928-w

First Results From the Retrieved Column O/N2 Ratio From the Ionospheric Connection Explorer (ICON): Evidence of the Impacts of Nonmigrating Tides

In near-Earth space, variations in thermospheric composition have important implications for thermosphere-ionosphere coupling. The ratio of O to N2 is often measured using far-UV airglow observations. Taking such airglow observations from space, looking below the Earth s limb allows for the total column of O and N2 in the ionosphere to be determined. While these observations have enabled many previous studies, determining the impact of nonmigrating tides on thermospheric composition has proved difficult, owing to a small contamination of the signal by recombination of ionospheric O+. New ICON observations of far-UV are presented here, and their general characteristics are shown. Using these, along with other observations and a global circulation model, we show that during the morning hours and at latitudes away from the peak of the equatorial ionospheric anomaly, the impact of nonmigrating tides on thermospheric composition can be observed. During March–April 2020, the column O/N2 ratio was seen to vary by 3–4\% of the zonal mean. By comparing the amplitude of the variation observed with that in the model, both the utility of these observations and a pathway to enable future studies is shown.

England, Scott; Meier, R.; Frey, Harald; Mende, Stephen; Stephan, Andrew; Krier, Christopher; Cullens, Chihoko; Wu, Yen-Jung; Triplett, Colin; Sirk, Martin; Korpela, Eric; Harding, Brian; Englert, Christoph; Immel, Thomas;

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

YEAR: 2021     DOI: 10.1029/2021JA029575

airglow; atmospheric composition; Atmospheric tides; thermosphere

Conjugate Photoelectron Energy Spectra Derived From Coincident FUV and Radio Measurements

We present a method for estimating incident photoelectrons energy spectra as a function of altitude by combining global scale far-ultraviolet (FUV) and radio-occultation (RO) measurements. This characterization provides timely insights important for accurate interpretation of ionospheric parameters inferred from the recently launched Ionospheric Connection Explorer (ICON) observations. Quantification of photoelectron impact is enabled by the fact that conjugate photoelectrons (CPEs) directly affect FUV airglow emissions but not RO measurements. We demonstrate a technique for estimation of photoelectron fluxes and their spectra by combining coincident ICON and COSMIC2 measurements and show that a significant fraction of ICON-FUV measurements is affected by CPEs during the winter solstice. A comparison of estimated photoelectron fluxes with measured photoelectron spectra is used to gain further insights into the estimation method and reveals consistent values within 10–60 eV.

Urco, J.; Kamalabadi, F.; Kamaci, U.; Harding, B.; Frey, H.; Mende, S.; Huba, J.; England, S.; Immel, T.;

Published by: Geophysical Research Letters      Published on:

YEAR: 2021     DOI: 10.1029/2021GL095839

airglow; conjugate photolectrons; COSMIC2; energy spectra; ICON

Daily Variability in the Terrestrial UV Airglow

New capability for observing conditions in the upper atmosphere comes with the implementation of global ultraviolet (UV) imaging from geosynchronous orbit. Observed by the NASA

Immel, Thomas; Eastes, Richard; McClintock, William; Mende, Steven; Frey, Harald; Triplett, Colin; England, Scott;

Published by: Atmosphere      Published on:

YEAR: 2020     DOI: 10.3390/atmos11101046

Daytime O/N2 Retrieval Algorithm for the Ionospheric Connection Explorer (ICON)

The NASA Ionospheric Connection Explorer Far-Ultraviolet spectrometer, ICON FUV, will measure altitude profiles of the daytime far-ultraviolet (FUV) OI 135.6 nm and N₂ Lyman-Birge-Hopfield (LBH) band emissions that are used to determine thermospheric density profiles and state parameters related to thermospheric composition; specifically the thermospheric column O/N₂ ratio (symbolized as ΣO/N₂). This paper describes the algorithm concept that has been adapted and updated from one previously applied with success to limb data from the Global Ultraviolet Imager (GUVI) on the NASA Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) mission. We also describe the requirements that are imposed on the ICON FUV to measure ΣO/N₂ over any 500-km sample in daytime with a precision of better than 8.7\%. We present results from orbit-simulation testing that demonstrates that the ICON FUV and our thermospheric composition retrieval algorithm can meet these requirements and provide the measurements necessary to address ICON science objectives.

Stephan, Andrew; Meier, R.; England, Scott; Mende, Stephen; Frey, Harald; Immel, Thomas;

Published by: Space Science Reviews      Published on: 01/2018

YEAR: 2018     DOI: 10.1007/s11214-018-0477-6

The ionospheric connection explorer mission: Mission goals and design

The Ionospheric Connection Explorer, or ICON, is a new NASA Explorer mission that will explore the boundary between Earth and space to understand the physical connection

Immel, Thomas; England, SL; Mende, SB; Heelis, RA; Englert, CR; Edelstein, J; Frey, HU; Korpela, EJ; Taylor, ER; Craig, WW; , others;

Published by: Space Science Reviews      Published on:

YEAR: 2018     DOI: 10.1007/s11214-017-0449-2

Inferring nighttime ionospheric parameters with the far ultraviolet imager onboard the ionospheric connection explorer

The Ionospheric Connection Explorer (ICON) Far Ultraviolet (FUV) imager, ICON FUV, will measure altitude profiles of OI 135.6 nm emissions to infer nighttime ionospheric parameters.

Kamalabadi, Farzad; Qin, Jianqi; Harding, Brian; Iliou, Dimitrios; Makela, Jonathan; Meier, RR; England, Scott; Frey, Harald; Mende, Stephen; Immel, Thomas;

Published by: Space science reviews      Published on:

YEAR: 2018     DOI:

The Far Ultra-Violet Imager on the Icon Mission

ICON Far UltraViolet (FUV) imager contributes to the ICON science objectives by providing remote sensing measurements of the daytime and nighttime atmosphere/ionosphere. During sunlit atmospheric conditions, ICON FUV images the limb altitude profile in the shortwave (SW) band at 135.6 nm and the longwave (LW) band at 157 nm perpendicular to the satellite motion to retrieve the atmospheric O/N₂ ratio. In conditions of atmospheric darkness, ICON FUV measures the 135.6 nm recombination emission of O+ ions used to compute the nighttime ionospheric altitude distribution. ICON Far UltraViolet (FUV) imager is a Czerny\textendashTurner design Spectrographic Imager with two exit slits and corresponding back imager cameras that produce two independent images in separate wavelength bands on two detectors. All observations will be processed as limb altitude profiles. In addition, the ionospheric 135.6 nm data will be processed as longitude and latitude spatial maps to obtain images of ion distributions around regions of equatorial spread F. The ICON FUV optic axis is pointed 20 degrees below local horizontal and has a steering mirror that allows the field of view to be steered up to 30 degrees forward and aft, to keep the local magnetic meridian in the field of view. The detectors are micro channel plate (MCP) intensified FUV tubes with the phosphor fiber-optically coupled to Charge Coupled Devices (CCDs). The dual stack MCP-s amplify the photoelectron signals to overcome the CCD noise and the rapidly scanned frames are co-added to digitally create 12-second integrated images. Digital on-board signal processing is used to compensate for geometric distortion and satellite motion and to achieve data compression. The instrument was originally aligned in visible light by using a special grating and visible cameras. Final alignment, functional and environmental testing and calibration were performed in a large vacuum chamber with a UV source. The test and calibration program showed that ICON FUV meets its design requirements and is ready to be launched on the ICON spacecraft.

Mende, S.; Frey, H.; Rider, K.; Chou, C.; Harris, S.; Siegmund, O.; England, S.; Wilkins, C.; Craig, W.; Immel, T.; Turin, P.; Darling, N.; Loicq, J.; Blain, P.; Syrstad, E.; Thompson, B.; Burt, R.; Champagne, J.; Sevilla, P.; Ellis, S.;

Published by: Space Science Reviews      Published on: 10/2017

YEAR: 2017     DOI: 10.1007/s11214-017-0386-0

The August 2011 URSI World Day campaign: Initial results

During a 10-day URSI World Day observational campaign beginning on August 1, 2011, an isolated, major geomagnetic storm occurred. On August 5,\ Kp\ reached values of 8^-and\ Dst\ dropped to -113\ nT. The occurrence of this isolated storm in the middle of a 10-day URSI World Day campaign provides and unprecedented opportunity to observe the coupling of solar wind energy into the magnetosphere and to evaluate the varied effects that occur in the coupled magnetosphere\textendashionosphere\textendashthermosphere system. Dramatic changes in the ionosphere are seen at every one of the active radar stations, extending from Greenland down to equatorial Peru in the American sector and at middle latitudes in Ukraine. Data from TIMED and THEMIS are shown to support initial interpretations of the observations, where we focus on processes in the middle latitude afternoon sector during main phase, and the formation of a dense equatorial ionosphere during storm recovery. The combined measurements strongly suggest that the changes in ionospheric conditions observed after the main storm phase can be attributed in large part to changes in the stormtime thermosphere. This is through the generation of disturbance dynamo winds and also global neutral composition changes that either reduce or enhance plasma densities in a manner that depends mainly upon latitude. Unlike larger storms with possibly more sustained forcing, this storm exhibits minimal effects of persistent meridional stormtime wind drag, and little penetration of solar wind electric potentials to low latitudes. It is, therefore, an outstanding example of an impulsive event that exhibits longer-term effects through modification of the background atmosphere.

Immel, Thomas; Liu, Guiping; England, Scott; Goncharenko, Larisa; Erickson, Philip; Lyashenko, Mykhaylo; Milla, Marco; Chau, Jorge; Frey, Harald; Mende, Stephen; Zhou, Qihou; Stromme, Anja; Paxton, Larry;

Published by: Journal of Atmospheric and Solar-Terrestrial Physics      Published on: 11/2015

YEAR: 2015     DOI: 10.1016/j.jastp.2015.09.005

Aeronomy; Ionosphere; Radar; thermosphere

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

Impacts of atmospheric ultrafast Kelvin waves on radio scintillations in the equatorial ionosphere

We present a statistical analysis of the amplitudes of GPS scintillations (S4 index) observed throughout 2008\textendash2010 using the satellite radio occultation measurements of the Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC). Here, for the first time, periodic variability in the occurrence of S4 is investigated using these data. Significant variations of S4 with periods of 2.5\textendash4 days (quasi-3 days) are identified from the observations during postsunset hours (1900\textendash2400 local time) between 15\textdegreeS\textendash 15\textdegreeN magnetic latitude during this 3 year interval. Coherence analyses of these variations with the geomagnetic Ap index, solar EUV irradiance, and atmospheric wind measurements from an equatorial mesosphere meteor radar at Thumba, India ( 8.5\textdegreeN, 77\textdegreeE) are performed, providing a measure of the relationship between variations in the scintillations and potential drivers. The quasi-3 day variations in S4 are found to covary with the variations of the three drivers examined. In particular, the S4 signatures are found to be coherent with the atmospheric ultrafast Kelvin (UFK) planetary waves characterized by the zonal wind measurements of the radar. This study shows that these UFK waves are as important as the solar and geomagnetic drivers in forcing the day-to-day variations of the occurrence of equatorial spread F.

Liu, Guiping; Immel, Thomas; England, Scott; Frey, Harald; Mende, Stephen; Kumar, Karanam; Ramkumar, Geetha;

Published by: Journal of Geophysical Research: Space Physics      Published on: 02/2013

YEAR: 2013     DOI: 10.1002/jgra.50139

day-to-day variability; Equatorial ionosphere; scintillation; Ultra Fast Kelvin planetary wave

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:

A method for determining the drift velocity of plasma depletions in the equatorial ionosphere using far-ultraviolet spacecraft observations

Park, SH; England, SL; Immel, TJ; Frey, HU; Mende, SB;

Published by: Journal of Geophysical Research: Space Physics      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:

Effect of atmospheric tides on the morphology of the quiet time, postsunset equatorial ionospheric anomaly

England, S.; Immel, T.; Sagawa, E.; Henderson, S.; Hagan, M.; Mende, S.; Frey, H.; Swenson, C.; Paxton, L.;

Published by: Journal of Geophysical Research      Published on: Jan-01-2006

YEAR: 2006     DOI: 10.1029/2006JA011795

Longitudinal variation of the E-region electric fields caused by atmospheric tides

England, S.; Maus, S.; Immel, T.; Mende, S.;

Published by: Geophysical Research Letters      Published on: Jan-01-2006

YEAR: 2006     DOI: 10.1029/2006GL027465

Cluster observation of plasma flow reversal in the magnetotail during a substorm

Lui, ATY; Zheng, Y; Zhang, Y; Livi, S; Reme, H; Dunlop, MW; Gustafsson, Georg; Mende, SB; Mouikis, C; Kistler, LM;

Published by:       Published on:

YEAR: 2006     DOI:

Near Simultaneous Observations of the Aurora From FUV, Particle and Photometric Instruments on DMSP-F16, TIMED, and IMAGE

Hecht, JH; Strickland, DJ; Knight, HK; Kochenash, AJ; Zhang, Y; Morrison, MD; Paxton, LJ; Mende, SB; Frey, HU; Burke, WJ; , others;

Published by:       Published on:

YEAR: 2005     DOI:

Control of the Equatorial Ionospheric Morphology by Atmospheric Tides: TIMED GUVI and IMAGE FUV Observations

England, SL; Immel, TJ; Sagawa, E; Henderson, S; Hagan, ME; Mende, SB; Frey, HU; Swenson, C; Paxton, LJ;

Published by:       Published on:

YEAR: 2005     DOI:

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

IMAGE-FUV observations of the October-November 2003 flare and magnetic storm effects on Earth

Immel, TT; Ostgaard, N; Strickland, DJ; Frey, HU; Mende, SB; Lu, G;

Published by:       Published on:

YEAR: 2004     DOI:

Magnetotail behavior during storm time “sawtooth injections”

Lui, ATY; Hori, T; Ohtani, S; Zhang, Y; Zhou, XY; Henderson, MG; Mukai, T; Hayakawa, H; Mende, SB;

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

YEAR: 2004     DOI:

Sudden solar wind dynamic pressure enhancements and dayside detached auroras: IMAGE and DMSP observations

Zhang, Y; Paxton, LJ; Immel, TJ; Frey, HU; Mende, SB;

Published by: Journal of geophysical research      Published on:

YEAR: 2003     DOI:

Negative ionospheric storms seen by the IMAGE FUV instrument

Data from the IMAGE SI-13 instrument are used to study depletions in the OI 135.6 nm dayglow intensity due to two magnetic storms observed on 8 June and 15 July 2000. Results show that the SI-13 instrument is sensitive to changes in the 135.6 nm dayglow caused by depletion of the O/N₂\ column density ratio. It is found that depletion levels in the SI-13 images are weaker than those in the true O/N₂\ values or electron density parameters, such as NmF2 (peak F2 electron density) due to the N₂\ LBH contribution in the SI-13 intensities. A depletion of -20\% (8 June 2000) and -50\% (15 July 2000) in the SI-13 intensities corresponds to -50\% and -90\% reductions in NmF2, respectively. AURIC simulations indicate that -67\% is the maximum depletion level that can be seen in the SI-13 intensities. The Millstone radar, digisonde and DMSP observations reveal that the electron density depletion extended from the low F-layer altitudes up to 840 km. Owing to the prevailing thermospheric circulation pattern, the depletions cover a wide area (at least 1/8 Earth surface) over the Northern Hemisphere for both of the cases. A deep depletion was always seen first in the morning side and then at later local times. The atmosphere took about 12 hours (8 June case) and more than 24 hours (15 July case) to recover. The results from the SI-13 images are in a good agreement with digisonde, radar, and DMSP observations. The depletion in the SI-13 intensity can be explained by the Joule and particle heating in the high-latitude regions. The heating has two effects: (1) The heated air is nitrogen-rich/oxygen-depleted and (2) a wind surge created by the heating in the night side moves the oxygen-deplete air upward and transports it to lower latitudes together with the neutral wind. Corotation with the Earth brings the oxygen-depleted air to the dayside.

Zhang, Y.; Paxton, L.J.; Kil, H.; Meng, C.-I.; Mende, S.~B.; Frey, H.~U.; Immel, T.~J.;

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

YEAR: 2003     DOI: 10.1029/2002JA009797

Atmospheric Composition and Structure: Airglow and aurora; Atmospheric Composition and Structure: Thermosphere-composition and chemistry; atmospheric composition change; depletion of OI 135.6 nm dayglow; Ionosphere: Ionospheric disturbances; Ionosphere: Plasma temperature and density; Magnetospheric Physics: Storms and substorms; negative ionospheric storms

TIMED Observations of the Signatures of Magnetic Activity in the MLTI Region placed into Global Context by ACE, POLAR, IMAGE, SAMPEX, FAST, NOAA/POES, and DMSP

Kozyra, JU; Liemohn, MW; Mlynczak, MG; Paxton, LJ; Skinner, WR; Baker, DN; Cattell, CA; Germany, GA; Mende, SB; Pollock, CJ;

Published by:       Published on:

YEAR: 2002     DOI: