Bibliography

Impacts of Binning Methods on High-Latitude Electrodynamic Forcing: Static Versus Boundary-Oriented Binning Methods

An outstanding issue in the general circulation model simulations for Earth\textquoterights upper atmosphere is the inaccurate estimation of Joule heating, which could be associated with the inaccuracy of empirical models for high-latitude electrodynamic forcing. The binning methods used to develop those empirical models may contribute to the inaccuracy. Traditionally, data are binned through a static binning approach by using fixed geomagnetic coordinates, in which the dynamic nature of the forcing is not considered and therefore the forcing patterns may be significantly smeared. To avoid the smoothing issue, data can be binned according to some physically important boundaries in the high-latitude forcing, that is, through a boundary-oriented binning approach. In this study, we have investigated the sensitivity of high-latitude forcing patterns to the binning methods by applying both static and boundary-oriented binning approaches to the electron precipitation and electric potential data from the Defense Meteorological Satellite Program satellites. For this initial study, we have focused on the moderately strong and dominantly southward interplanetary magnetic field conditions. As compared with the static binning results, the boundary-oriented binning approach can provide a more confined and intense electron precipitation pattern. In addition, the magnitudes of the electric potential and electric field in the boundary-oriented binning results increase near the convection reversal boundary, leading to a ~11\% enhancement of the cross polar cap potential. The forcing patterns obtained from both binning approaches are used to drive the Global Ionosphere and Thermosphere Model to assess the impacts on Joule heating by using different binning patterns. It is found that the hemispheric-integrated Joule heating in the simulation driven by the boundary-oriented binning patterns is 18\% higher than that driven by the static binning patterns.

Zhu, Qingyu; Deng, Yue; Richmond, Arthur; Maute, Astrid; Chen, Yun-Ju; Hairston, Marc; Kilcommons, Liam; Knipp, Delores; Redmon, Robert; Mitchell, Elizabeth;

Published by: Journal of Geophysical Research: Space Physics      Published on: 01/2020

YEAR: 2020     DOI: 10.1029/2019JA027270

Electric field; high latitude; Joule heating; particle precipitation

Hemispheric asymmetry of the dayside aurora due to imbalanced solar insolation

Liou, Kan; Mitchell, Elizabeth;

Published by: Scientific Reports      Published on:

YEAR: 2020     DOI:

Effects of the interplanetary magnetic field y component on the dayside aurora

A dawn\textendashdusk asymmetry in many high-latitude ionospheric and magnetospheric phenomena, including the aurora, can be linked to the east\textendashwest (y) component of the interplanetary magnetic field (IMF). Owing to the scarcity of observations in the Southern Hemisphere, most of the previous findings are associated with the Northern Hemisphere. It has long been suspected that if the IMF B_y component also produces a dawn\textendashdusk asymmetry and/or a mirror image in the Southern Hemisphere as predicted by some theories. The present study explores the effect of the IMF B_y component on the dayside aurora from both hemispheres by analyzing the auroral emission data from the Global UltraViolet scanning spectrograph Imager on board the Thermosphere Ionosphere Mesosphere Energetics and Dynamics mission spacecraft from 2002 to 2007. The data set comprises 28,774 partial images of the northern hemispheric oval and 29,742 partial images of the southern hemispheric oval, allowing for a statistical analysis. It is found that even though auroras in different regions of the dayside oval respond differently to the orientation of the IMF B_y component, their responses are opposite between the two hemispheres. For example, at ~ 1400\textendash1600\ MLT in the Northern Hemisphere, where the so-called 1500\ MLT auroral hot spots occur, peak auroral energy flux is larger for negative IMF B_y comparing to positive IMF B_y. The response is reversed in the Southern Hemisphere. The present study also suggests that the total energy flux does not change with the IMF B_y orientation change. This result is consistent with a larger (smaller) convection vortex in the postnoon sector for IMF B_y \< 0 (B_y \> 0) resulting from anti-parallel merging.

Liou, K.; Mitchell, E.;

Published by: Geoscience Letters      Published on: 11/2019

YEAR: 2019     DOI: 10.1186/s40562-019-0141-3

Hemispheric Asymmetry of the Premidnight Aurora Associated With the Dawn-Dusk Component of the Interplanetary Magnetic Field

It has been known for decades that the nightside aurora in the Northern Hemisphere (NH) tends to be brighter when the interplanetary magnetic field (IMF) measured at Earth has a dawnward (negative y) component compared to a duskward (positive y) component. This asymmetric response to the polarity of IMF B_y has been explained by an interhemispheric current flowing out of the NH due to a nonuniform \textquotedblleftpenetration\textquotedblright of IMF B_y onto the magnetotail. If such a hypothesis is correct, it should predict a brighter aurora in the nightside Southern Hemisphere (SH) for positive IMF B_y than negative IMF B_y. Here we investigate this hypothesis using Thermosphere, Ionosphere, Mesosphere, Energetics and Dynamics/Global Ultraviolet Imager data. The present study not only reproduces the result previously found in NH but also shows an opposite change to its Northern Hemispheric counterpart in SH in response to the different IMF B_y polarity. When comparing north to south, for negative IMF B_y, the premidnight auroral energy flux is greater in NH than that in SH. The result becomes opposite for positive IMF B_y. This result is consistent with the hypothesis of the existence of an interhemispheric field-aligned current.

Liou, K.; Mitchell, E.;

Published by: Journal of Geophysical Research: Space Physics      Published on: 02/2019

YEAR: 2019     DOI: 10.1029/2018JA025953

North-south Asymmetry in Dayside Auroras Associated With Local Sunlight Conditions

Mitchell, Elizabeth; Liou, Kan;

Published by:       Published on:

YEAR: 2019     DOI:

Advances in Auroral Studies I

Zhang, Yongliang; Paxton, Larry; Robinson, Robert; MacDonald, Elizabeth; Mitchell, Elizabeth;

Published by:       Published on:

YEAR: 2019     DOI:

A case study comparing citizen science aurora data with global auroral boundaries derived from satellite imagery and empirical models

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:

Material flux from the rings of Saturn into its atmosphere

Perry, ME; , Waite; Mitchell, DG; Miller, KE; Cravens, TE; Perryman, RS; Moore, L; Yelle, RV; Hsu, H-W; Hedman, MM; , others;

Published by: Geophysical Research Letters      Published on:

YEAR: 2018     DOI:

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:

Validating Local Responses in OVATION Prime-2013 and OVATION-SM with DMSP SSUSI

Mitchell, Elizabeth; Schaefer, Robert; Paxton, Larry;

Published by:       Published on:

YEAR: 2016     DOI:

Ionospheric data assimilation and forecasting during storms

Chartier, Alex; Matsuo, Tomoko; Anderson, Jeffrey; Collins, Nancy; Hoar, Timothy; Lu, Gang; Mitchell, Cathryn; Coster, Anthea; Paxton, Larry; Bust, Gary;

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

YEAR: 2016     DOI:

NASA Timed Guvi and Dmsp Ssusi Observations of the St. Patricks Day Storm of

Paxton, Larry; Zhang, Yongliang; Kil, Hyosub; Mitchell, Elizabeth; Schaefer, Robert;

Published by: 41st COSPAR Scientific Assembly      Published on:

YEAR: 2016     DOI:

Link between pre-midnight second harmonic poloidal waves and auroral undulations: Conjugate observations with a Van Allen Probes spacecraft and a THEMIS all-sky imager

We report, for the first time, an auroral undulation event on 1 May 2013 observed by an all-sky imager (ASI) at Athabasca (L = 4.6), Canada, for which in situ field and particle measurements in the conjugate magnetosphere were available from a Van Allen Probes spacecraft. The ASI observed a train of auroral undulation structures emerging spontaneously in the pre-midnight subauroral ionosphere, during the growth phase of a substorm. The undulations had an azimuthal wavelength of ~180 km and propagated westward at a speed of 3\textendash4 km s^-1. The successive passage over an observing point yielded quasi-periodic oscillations in diffuse auroral emissions with a period of ~40 s. The azimuthal wave number m of the auroral luminosity oscillations was found to be m ~ -103. During the event the spacecraft \textendash being on tailward stretched field lines ~0.5 R_E outside the plasmapause that mapped into the ionosphere conjugate to the auroral undulations \textendash encountered intense poloidal ULF oscillations in the magnetic and electric fields. We identify the field oscillations to be the second harmonic mode along the magnetic field line through comparisons of the observed wave properties with theoretical predictions. The field oscillations were accompanied by oscillations in proton and electron fluxes. Most interestingly, both field and particle oscillations at the spacecraft had one-to-one association with the auroral luminosity oscillations around its footprint. Our findings strongly suggest that this auroral undulation event is closely linked to the generation of second harmonic poloidal waves

Motoba, T.; Takahashi, K.; Ukhorskiy, A.; Gkioulidou, M.; Mitchell, D.; Lanzerotti, L.; Korotova, G.; Donovan, E.; Wygant, J.; Kletzing, C.; Kurth, W.; Blake, J.;

Published by: Journal of Geophysical Research: Space Physics      Published on: 02/2015

YEAR: 2015     DOI: 10.1002/2014JA020863

GPS phase scintillation at high latitudes during geomagnetic storms of 7—17 March 2012—Part 2: Interhemispheric comparison

During the ascending phase of solar cycle 24, a series of interplanetary coronal mass ejections (ICMEs) in the period 7–17 March 2012 caused geomagnetic storms that strongly

Prikryl, P; Ghoddousi-Fard, R; Spogli, L; Mitchell, CN; Li, G; Ning, B; Cilliers, PJ; , Sreeja; Aquino, M; Terkildsen, M; , others;

Published by:       Published on:

YEAR: 2015     DOI: 10.5194/angeo-33-637-2015

Auroral precipitation models and space weather

Newell, Patrick; Liou, Kan; Zhang, Yongliang; Sotirelis, Thomas; Mitchell, EJ; Mitchell, Elizabeth;

Published by: Auroral dynamics and space weather      Published on:

YEAR: 2015     DOI:

Auroral precipitation models and space weather

Newell, Patrick; Liou, Kan; Zhang, Yongliang; Sotirelis, Thomas; Mitchell, EJ; Mitchell, Elizabeth;

Published by: Auroral dynamics and space weather      Published on:

YEAR: 2015     DOI:

OVATION Prime-2013: Extension of auroral precipitation model to higher disturbance levels

OVATION Prime (OP) is an auroral precipitation model parameterized by solar wind driving. Distinguishing features of the model include an optimized solar wind-magnetosphere coupling function (dΦ_MP/dt) which predicts auroral power significantly better than\ Kp\ or other traditional parameters, the separation of aurora into categories (diffuse aurora, monoenergetic, broadband, and ion), the inclusion of seasonal variations, and separate parameter fits for each magnetic latitude (MLAT) \texttimes magnetic local time (MLT) bin, thus permitting each type of aurora and each location to have differing responses to season and solar wind input\textemdashas indeed they do. We here introduce OVATION Prime-2013, an upgrade to the 2010 version currently widely available. The most notable advantage of OP-2013 is that it uses UV images from the GUVI instrument on the satellite TIMED for high disturbance levels (dΦ_MP/dt \> 1.2 MWb/s which roughly corresponds toKp = 5+ or 6-). The range of validity is approximately 0 \< dΦ_MP/dt <= 3.0 MWb/s (Kp\ about 8+). Other upgrades include a reduced susceptibility to salt-and-pepper noise, and smoother interpolation across the postmidnight data gap. The model is tested against an independent data set of hemispheric auroral power from Polar UVI. Over the common range of validity of OP-2010 and OP-2013, the two models predict auroral power essentially identically, primarily because hemispheric power calculations were done in a way to minimize the impact of OP-2010s noise. To quantitatively demonstrate the improvement at high disturbance levels would require multiple very large substorms, which are rare, and insufficiently present in the limited data set of Polar UVI hemispheric power values. Nonetheless, although OP-2010 breaks down in a variety of ways above\ Kp = 5+ or 6-, OP-2013 continues to show the auroral oval advancing equatorward, at least to 55\textdegree MLAT or a bit less, and OP-2013 does not develop spurious large noise patches. We will also discuss the advantages and disadvantages of other precipitation models more generally, as no one model fits best all possible uses.

Newell, P.; Liou, K.; Zhang, Y.; Sotirelis, T.; Paxton, L.; Mitchell, E.;

Published by: Space Weather      Published on: 06/2014

YEAR: 2014     DOI: 10.1002/swe.v12.610.1002/2014SW001056

AURORA; precipitation; forecasting

Developing a Multi-Element Geospace Investigation to Understand the Impact of Hemispheric Assymetry

Paxton, Larry; Newell, Patrick; Stromme, Anja; Ridley, Aaron; Kozyra, Janet; Mitchell, Elizabeth;

Published by:       Published on:

YEAR: 2014     DOI:

The Role of Thermospheric Composition in Ionospheric Forecasting

Chartier, A; Morgan, F; Bust, GS; Mitchell, CN;

Published by:       Published on:

YEAR: 2014     DOI:

OVATION Prime-2013: Solar Wind Driven Precipitation Model Extended to Higher Geomagnetic Activity Levels

Newell, Patrick; Liou, Kan; Zhang, Yongliang; Sotirelis, Thomas; Paxton, Larry; Mitchell, Elizabeth;

Published by:       Published on:

YEAR: 2014     DOI:

Accomplishing Transformative Research in a Challenging Fiscal Environment

Mitchell, Elizabeth; Paxton, Larry; Bust, G;

Published by:       Published on:

YEAR: 2014     DOI:

Evidence of auroral oval TEC enhancement and simultaneous plasma patch break-off events in the Arctic and Antarctic ionosphere during the initial phase of a geomagnetic storm event at equinox, 26 September 2011

Kinrade, Joe; Mitchell, Cathryn; Paxton, Larry; Bust, Gary;

Published by:       Published on:

YEAR: 2013     DOI:

An interhemispheric comparison of GPS phase scintillation with auroral emission observed at the South Pole and from the DMSP satellite

The global positioning system (GPS) phase scintillation caused by highlatitude ionospheric irregularities during an intense high-speed stream (HSS) of the solar wind from April 29 to May 5, 2011, was observed using arrays of GPS ionospheric scintillation and total electron content monitors in the Arctic and Antarctica. The one-minute phase-scintillation index derived from the data sampled at 50 Hz was complemented by a proxy index (delta phase rate) obtained from 1-Hz GPS data. The scintillation occurrence coincided with the aurora borealis and aurora australis observed by an all-sky imager at the South Pole, and by special sensor ultraviolet scanning imagers on board satellites of the Defense Meteorological Satellites Program. The South Pole (SP) station is approximately conjugate with two Canadian High Arctic Ionospheric Network stations on Baffin Island, Canada, which provided the opportunity to study magnetic conjugacy of scintillation with support of riometers and magnetometers. The GPS ionospheric pierce points were mapped at their actual or conjugate locations, along with the auroral emission over the South Pole, assuming an altitude of 120 km. As the aurora brightened and/or drifted across the field of view of the all-sky imager, sequences of scintillation events were observed that indicated conjugate auroras as a locator of simultaneous or delayed bipolar scintillation events. In spite of the greater scintillation intensity in the auroral oval, where phase scintillation sometimes exceeded 1 radian during the auroral break-up and substorms, the percentage occurrence of moderate scintillation was highest in the cusp. Interhemispheric comparisons of bipolar scintillation maps show that the scintillation occurrence is significantly higher in the southern cusp and polar cap.

Prikryl, Paul; Zhang, Yongliang; Ebihara, Yusuke; Ghoddousi-Fard, Reza; Jayachandran, Periyadan; Kinrade, Joe; Mitchell, Cathryn; Weatherwax, Allan; Bust, Gary; Cilliers, Pierre; , others;

Published by: Annals of Geophysics      Published on:

YEAR: 2013     DOI:

An interhemispheric comparison of GPS phase scintillation with auroral emission observed at South Pole and from DMSP satellite

Prikryl, Paul; Zhang, Yongliang; Ebihara, Yusuke; Ghoddousi-Fard, Reza; Jayachandran, Periyadan; Kinrade, Joe; Mitchell, Cathryn; Weatherwax, Allan; Bust, Gary; Cilliers, Pierre; , others;

Published by: Annals of Geophysics      Published on:

YEAR: 2013     DOI:

Scintillation-producing Fresnel-scale irregularities associated with the regions of steepest TEC gradients adjacent to the equatorial ionization anomaly

Muella, M.; Kherani, E.; de Paula, E.; Cerruti, A.; Kintner, P.; Kantor, I.; Mitchell, C.; Batista, I.; Abdu, M.;

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

YEAR: 2010     DOI: 10.1029/2009JA014788

Disturbed time observations of the temporal dependence and dynamics of TEC, scintillation, and ionospheric irregularity zonal drifts

Muella, Marcio; de Paula, Eurico; Kintner, Paul; Kantor, Ivan; Cerruti, Alessandro; Mitchell, Cathryn; Crowley, Geoff; Smorigo, Paulo; Batista, Inez;

Published by: 37th COSPAR Scientific Assembly      Published on:

YEAR: 2008     DOI:

Ionospheric storm time dynamics as seen by GPS tomography and in situ spacecraft observations

During major geomagnetic storms anomalous enhancements of the ionospheric density are seen at high and middle latitudes. A number of physical mechanisms have been invoked to explain these storm time density anomalies including an expansion of high-latitude electric plasma convection to midlatitudes, thermospheric neutral winds, and changes in the ionospheric composition. However, it remains unclear which mechanism plays the dominant role in the formation of storm time density anomalies, partly because of insufficient coverage of the measurements of global electric convection and thermospheric winds at midlatitudes. This paper describes a novel technique for extracting the storm time E × B convection boundary from in situ measurements of plasma bulk motion obtained by LEO DMSP satellites. The convection boundary estimated from the DMSP data during major magnetic storm of 20 November 2003 has been compared with the global distributions of the ionospheric plasma deduced from characteristics of GPS signals acquired by a ground-based network of GPS receivers. The tomographic inversion of GPS data using a three-dimensional time-dependent inversion technique reveals the spatial and temporal evolution of the storm time density anomaly. Comparison between the tomographic reconstructions of the ionospheric plasma distributions and in situ DMSP measurements of plasma bulk motion suggests that the convective flow expanded low enough in latitude to encompass, in part, the formation of the midlatitude TEC anomaly. Some features of the TEC dynamics observed during the 20 November 2003 storm, however, suggest that mechanisms other than the expanded ionospheric convection (such as thermospheric neutral winds) are also involved in the formation of the midlatitude anomaly.

Pokhotelov, D.; Mitchell, C.; Spencer, P.; Hairston, M.; Heelis, R.;

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

YEAR: 2008     DOI: https://doi.org/10.1029/2008JA013109

Ionospheric storms; Tomography; plasma convection

Parametric analysis of nightside conductance effects on inner magnetospheric dynamics for the 17 April 2002 storm

Liemohn, Michael; Ridley, Aaron; Brandt, Pontus; Gallagher, Dennis; Kozyra, Janet; Ober, Daniel; Mitchell, Donald; Roelof, Edmond; DeMajistre, Robert;

Published by: Journal of Geophysical Research: Space Physics      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:

GUVI/TIMED Observations of the auroral inputs and thermospheric response during the October and November 2003 Superstorms

Zhang, Y; Paxton, LJ; Kozyra, JU; DeMajistre, R; Kil, H; Morrison, D; Wolven, B; Brandt, PC; Mitchell, DG; Talaat, E;

Published by:       Published on:

YEAR: 2004     DOI:

Global ring current pressure during geomagnetic storms: solar wind and storm phase dependence

Brandt, PC; Roelof, EC; DeMajistre, R; Mitchell, DG; Vallat, C; Dandouras, I;

Published by:       Published on:

YEAR: 2004     DOI:

Conductance Effects on Inner Magnetospheric Plasma Morphology: Model Comparisons With IMAGE EUV, MENA, and HENA Data

Liemohn, MW; Ridley, AJ; Kozyra, JU; Gallagher, DL; Henderson, MG; Denton, MH; Jahn, J; Roelof, EC; DeMajistre, R; Mitchell, DG; , others;

Published by:       Published on:

YEAR: 2004     DOI:

Extracting energetic ion distributions from energetic neutral atom images of space plasmas

DeMajistre, R; Roelof, EC; Mitchell, DG; , others;

Published by:       Published on:

YEAR: 2004     DOI:

Advanced time-of-flight system-on-a-chip for remote sensing instruments

Paschalidis, Nicholas; Stamatopoulos, Nick; Karadamoglou, Kosta; Kottaras, George; Paschalidis, Vasilis; Sarris, Emmanuel; Mitchell, Donald; Humm, David; Paxton, Larry; McNutt, Ralph;

Published by:       Published on:

YEAR: 2003     DOI:

Storm-time ion pressure distribution of the inner magnetosphere

Brandt, PC; Roelof, EC; DeMajistre, R; Lui, AT; Mitchell, DG; Anderson, BJ; Ohtani, S; Fok, M-C;

Published by:       Published on:

YEAR: 2003     DOI:

Substorm Local Time and Compositional Characteristics During the April, 2002 Geomagnetic Storms

Mitchell, DG; Ohtani, S; Roelof, EC; DeMajistre, R; Reeves, G; Henderson, M; Skoug, R; Borovsky, J; , others;

Published by:       Published on:

YEAR: 2002     DOI: