Bibliography

Chapter 4 - Energetic particle dynamics, precipitation, and conductivity

This chapter reviews cross-scale coupling and energy transfer in the magnetosphere-ionosphere-thermosphere system via convection, precipitation, and conductance. It begins with an introduction into Earth’s plasma sheet characteristics including particles, plasma moments, and magnetic fields, and their dependence on solar wind and interplanetary magnetic field parameters. Section 4.2 transitions to observations of the magnetosphere convection, precipitation, and coupling with the ionosphere on multiple scales, with Section 4.3 focusing on related global modeling efforts for particle precipitation. This chapter describes basic concepts and principles of major pitch angle scattering processes—wave-particle interactions and field-line curvature scattering—as well as the resulting precipitation and conductance. Section 4.4 continues the discussion started in 4.2 Observations of multiscale convection, precipitation, and conductivity, 4.3 Simulating particle precipitation of magnetospheric origin in global models regarding the resulting ionosphere conductance, delving more deeply into empirical and data assimilative techniques. This chapter describes techniques used over the years to observe and model precipitation and conductance on multiple scales.

Gabrielse, Christine; Kaeppler, Stephen; Lu, Gang; Wang, Chih-Ping; Yu, Yiqun; Nishimura, Yukitoshi; Verkhoglyadova, Olga; Deng, Yue; Zhang, Shun-Rong;

Published by:       Published on: jan

YEAR: 2022     DOI: 10.1016/B978-0-12-821366-7.00002-0

Conductance; Conductivity; Convection; particle precipitation

Impact of Soft Electron Precipitation on the Thermospheric Neutral Mass Density During Geomagnetic Storms: GITM Simulations

In this study, the impact of improving soft (0.1–1 keV) electron precipitation on the F-region neutral mass density has been evaluated using the Global Ionosphere Thermosphere Model (GITM). Two types of electron energy spectra having the same total energy flux and average energy but different spectral shapes have been used to specify the electron precipitation in GITM. One is the Maxwellian spectrum and the other is from an empirical model, Auroral Spectrum and High-Latitude Electric field variabilitY (ASHLEY), which provides stronger (up to 2–3 orders of magnitude) soft electron precipitations than the Maxwellian spectrum. Data-model comparisons indicate that the storm-time orbital averaged neutral density can be increased by 10\%–40\% and is more consistent with the observation if the non-Maxwellian ASHLEY spectrum is used. This study reveals the importance of accurate soft electron precipitation specifications in the whole auroral zone to improving the F-region neutral mass density estimations.

Zhu, Qingyu; Deng, Yue; Sheng, Cheng; Anderson, Philip; Bukowski, Aaron;

Published by: Geophysical Research Letters      Published on:

YEAR: 2022     DOI: 10.1029/2021GL097260

ASHLEY; GITM; neutral mass density; soft electron precipitation

Geomagnetic and Solar Dependencies of Midlatitude E-Region Irregularity Occurrence Rate: A Climatology Based on Wuhan VHF Radar Observations

By using Wuhan VHF radar, we show the morphological features of E-region field-aligned irregularity (FAI) occurrence at Wuhan during 2015–2020. Statistical results present that E-region FAI occurrence reaches a maximum after sunset in summer season. According to Doppler spectrum features, type-2 irregularity is predominantly observed at Wuhan. In addition, we observed a remarkable correlation between E-region FAI occurrence and geomagnetic activity, which includes periods of positive correlation and negative correlation depending on different geomagnetic conditions. The strong negative correlation also exists between E-region FAI occurrence and solar activity. In our observed results, we find that E-region FAI occurrence shows a strong linkage with local sporadic E (ES) layer. A quantitative analysis of linear theory of plasma instability in the E-region at midlatitudes is also presented in our study. The calculated results of linear growth rate indicate the importance of plasma density gradient of local ES layer and field-line-integrated Pedersen conductivity on the generation of E-region FAI. The geomagnetic and solar variations of E-region FAI occurrence are also discussed in this study, which show a dependence on the geomagnetic and solar variations of both meteor rate and medium-scale traveling ionospheric disturbance occurrence.

Liu, Yi; Zhou, Chen; Xu, Tong; Deng, Zhongxin; Du, Zhitao; Lan, Ting; Tang, Qiong; Zhu, Yunzhou; Wang, Zhuangkai; Zhao, Zhengyu;

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

YEAR: 2022     DOI: 10.1029/2021JA029597

Progresses and Challenges to specifying the IT system during weak storms

Deng, Yue; Heelis, Roderick; Paxton, Larry; Lyons, Larry; Nishimura, Toshi; Zhang, Shunrong; Bristow, Bill; Maute, Astrid; Sheng, Cheng; Zhu, Qingyu; , others;

Published by:       Published on:

YEAR: 2021     DOI:

Estimating Precipitating Energy Flux, Average Energy, and Hall Auroral Conductance From THEMIS All-Sky-Imagers With Focus on Mesoscales

Recent attention has been given to mesoscale phenomena across geospace (∼10 s km to 500 km in the ionosphere or ∼0.5 RE to several RE in the magnetosphere), as their contributions to the system global response are important yet remain uncharacterized mostly due to limitations in data resolution and coverage as well as in computational power. As data and models improve, it becomes increasingly valuable to advance understanding of the role of mesoscale phenomena contributions—specifically, in magnetosphere-ionosphere coupling. This paper describes a new method that utilizes the 2D array of Time History of Events and Macroscale Interactions during Substorms (THEMIS) white-light all-sky-imagers (ASI), in conjunction with meridian scanning photometers, to estimate the auroral scale sizes of intense precipitating energy fluxes and the associated Hall conductances. As an example of the technique, we investigated the role of precipitated energy flux and average energy on mesoscales as contrasted to large-scales for two back-to-back substorms, finding that mesoscale aurora contributes up to ∼80\% (∼60\%) of the total energy flux immediately after onset during the early expansion phase of the first (second) substorm, and continues to contribute ∼30–55\% throughout the remainder of the substorm. The average energy estimated from the ASI mosaic field of view also peaked during the initial expansion phase. Using the measured energy flux and tables produced from the Boltzmann Three Constituent (B3C) auroral transport code (Strickland et al., 1976; 1993), we also estimated the 2D Hall conductance and compared it to Poker Flat Incoherent Scatter Radar conductance values, finding good agreement for both discrete and diffuse aurora.

Gabrielse, Christine; Nishimura, Toshi; Chen, Margaret; Hecht, James; Kaeppler, Stephen; Gillies, Megan; Reimer, Ashton; Lyons, Larry; Deng, Yue; Donovan, Eric; Evans, Scott;

Published by: Frontiers in Physics      Published on:

YEAR: 2021     DOI:

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

Understanding the Behavior of the Ionosphere—Thermosphere—Mesosphere at Solar Minimum I

Paxton, Larry; Deng, Yue; Liu, Huixin; Fang, Tzu-Wei;

Published by:       Published on:

YEAR: 2020     DOI:

Comparison of the Thermospheric Nitric Oxide Emission Observations and the GITM Simulations: Sensitivity to Solar and Geomagnetic Activities

An accurate estimate of the energy budget (heating and cooling) of the ionosphere and thermosphere, especially during space weather events, has been a challenge. The abundance of Nitric Oxide (NO), a minor species in the thermosphere, is an important component of energy balance here because its production comes from energy sources able to break the strong bond of molecular nitrogen, and infrared emissions from NO play an important role in thermospheric cooling. Recent studies have significantly improved our understanding of NO chemistry and its relationship to energy deposition in the thermospheric photochemical reactions. In this study, the chemical scheme in the Global Ionosphere Thermosphere Model (GITM) is updated to better predict the lower thermospheric NO responses to solar and geomagnetic activity. We investigate the sensitivity of the 5.3-micron NO emission to F10.7 and Ap indices by comparing the global integrated emission from GITM with an empirical proxy derived from the Sounding of the Atmosphere using Broadband Emission Radiometry measurements. GITM\textquoterights total emission agrees well within 20\% of the empirical values. The updated chemistry scheme significantly elevates the level of integrated emission compared to the previous scheme. The inclusion of N2(A)-related production of NO contributes an additional 5-25\% to the emission. Localized enhancement of ~70\% in column density and a factor of three in column emission are simulated at a moderate geomagnetic level.

Lin, Cissi; Deng, Yue; Venkataramani, Karthik; Yonker, Justin; Bailey, Scott;

Published by: Journal of Geophysical Research: Space Physics      Published on: 10/2018

YEAR: 2018     DOI: 10.1029/2018JA025310

Comparison of the Thermospheric Nitric Oxide Emission Observations and the Global Ionosphere-Thermosphere Model (GITM) Simulations: Sensitivity to Solar and Geomagnetic Activities

The magnitude of enhancement observed in column density agrees well with the cases observed by TIMED/GUVI −8 W/m3) agree well with TIMED/SABER and GUVI measurements.

Lin, Cissi; Deng, Yue; Venkataramani, Karthik; Yonker, Justin; Bailey, Scott;

Published by: arXiv preprint arXiv:1807.01380      Published on:

YEAR: 2018     DOI: https://doi.org/10.48550/arXiv.1807.01380

Development of a new aurora model for the small-and meso-scale structures through deep-learning methods and their influence on the upper atmosphere

Deng, Y; Chen, Z; , Wang; Sheng, Cheng; , Jin; Zhang, Yongliang; Paxton, Larry; Deng, Xiaohua; Huang, Chung-Ming;

Published by:       Published on:

YEAR: 2018     DOI:

Development of a new aurora model for the small-and meso-scale structures through deep-learning methods and their influence on the upper atmosphere

Deng, Y; Chen, Z; , Wang; Sheng, Cheng; , Jin; Zhang, Yongliang; Paxton, Larry; Deng, Xiaohua; Huang, Chung-Ming;

Published by:       Published on:

YEAR: 2018     DOI:

Parameterization of Nitric Oxide Emissions in the Thermosphere

Lin, CYT; Deng, Yue; Venkataramani, Karthik; Yonker, Justin; Bailey, Scott;

Published by:       Published on:

YEAR: 2016     DOI:

Height-integrated Pedersen conductivity in both E and F regions from COSMIC observations

Altitudinal distribution of Joule heating is very important to the thermosphere and ionosphere, which is roughly proportional to the Pedersen conductance at high latitudes. Based on the Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) satellites observations from 2008 to 2011, the height-integrated Pedersen conductivities in both E (100\textendash150\ km) and F (150\textendash600\ km) regions and their ratio _γPγP (_∑PE/_∑PF∑PE/∑PF) have been calculated. The result shows that the maximum ratio in the northern summer hemisphere is ~5.5, which is smaller than that from the Thermosphere\textendashIonosphere\textendashElectrodynamics General Circulation Model (TIE-GCM v1.94) simulation (~9). This indicates that the energy inputs into the F region may be underestimated in the model. The seasonal variations of the ratio have been investigated for both hemispheres, and an interhemispheric asymmetry has been identified. The variational trend of the ratio is similar in both hemispheres, which reaches minimum at local summer and maximum at local winter. However, the difference of the ratio from local summer to local winter in the southern hemisphere is larger than that in the northern hemisphere.

Sheng, Cheng; Deng, Yue; Yue, Xinan; Huang, Yanshi;

Published by: Journal of Atmospheric and Solar-Terrestrial Physics      Published on: 08/2014

YEAR: 2014     DOI: 10.1016/j.jastp.2013.12.013

COSMIC; Interhemispheric asymmetry; Joule heating; Pedersen conductivity

Ionization due to electron and proton precipitation during the August 2011 storm

The parameterizations of monoenergetic particle impact ionization in Fang et al. (2010) (Fang2010) and Fang et al. (2013) (Fang2013) are applied to the complex energy spectra measured by DMSP F16 satellite to calculate the ionization rates from electron and ion precipitations for a Northern Hemisphere pass from 0030 UT to 0106 UT on 6 August 2011. Clear enhancement of electron flux is found in the polar cap. The mean electron energy in the polar cap is mostly above 100 eV, while the mean energy in the auroral zone is typically above 1 keV. At the same time, F16 captures a strong Poynting flux enhancement in the polar cap, which is comparable to those in the auroral zone. The particle impact ionization rates using Fang2010 and Fang2013 parameterizations show clear enhancement at F region altitudes mainly due to the low-energy precipitating electrons, peaking probably in the cusp but also showing enhanced levels throughout most of the polar cap region. The general circulation models (GCMs), National Center for Atmospheric Research Thermosphere-Ionosphere-Electrodynamics General Circulation Model, and Global Ionosphere-Thermosphere Model, using their default empirical formulations of particle impact ionization, do not capture the observed features shown in the total particle ionization rate applying the Fang2010 and Fang2013 parameterizations to DMSP measurements. The difference between GCM simulations and Fang2010 and Fang2013 applied to DMSP data is due to the difference of both the inputs to the models and the parameterization of the ionization rates.

Huang, Yanshi; Huang, Cheryl; Su, Yi-Jiun; Deng, Yue; Fang, Xiaohua;

Published by: Journal of Geophysical Research: Space Physics      Published on: 04/2014

YEAR: 2014     DOI: 10.1002/2013JA019671

Fang 2010 parameterization; Fang 2013 parameterization; particle impact ionization; polar cap

GNSS radio occultation (RO) derived electron density quality in high latitude and polar region: NCAR-TIEGCM simulation and real data evaluation

Global Navigation Satellite System (GNSS) based radio occultation (RO) technique has shown powerful ability in ionospheric electron density profiling in the past decade. The most frequently used Abel inversion method in electron density retrieval has some biases because of the used spherical symmetry assumption. Our previous series simulations and evaluations mainly concentrated in the middle and low latitude regions have shown some systematical bias especially in lower altitude of low latitude region. However, the RO derived electron density quality in the high latitude and polar region is rarely investigated and not quantitatively clear yet. In this study, the Abel inversion error over high latitude and polar regions are systematically investigated for the first time based on NCAR-TIEGCM simulations and real data evaluations. The TIMED data driven NCAR-TIEGCM modeled electron density during 2008 are used to simulate the COSMIC RO events. The Abel inversion error can then be estimated by comparing Abel retrievals from TIEGCM simulated occultation with the original TIEGCM simulations. The Abel inversion can reproduce the season, altitude, latitude, and local time variation patterns of electron density and auroral zone electron density nighttime enhancement well in high latitude and polar region. The Abel inversion tends to underestimate the electron density in the auroral zone and overestimate it on both the equatorward and poleward sides of the auroral zone. As simulated by the TIEGCM model, the significant relative error (\>25\%) mainly occurs in lower altitude (\<250\ km) inside and around auroral zone region. Above 250\ km, the relative error mostly is less than 25\%. Specifically, RMSE (root mean square error) of NmF2 error from simulation is \~8.5\%. The Abel error under real ionosphere situation would be worse because the ionosphere could be more complicated and noisier than the model simulation. The error distribution and its seasonal, local time and latitude variations can be explained by the spherical symmetry assumption used in the Abel inversion associated with the corresponding ionospheric electron density variations. The comparisons between PFISR and COSMIC RO electron density during 2007\textendash2011 and some previous validation studies agree well with our simulation results. We hope these results can stimulate more studies in high latitude ionospheric research using RO data.

Yue, Xinan; Schreiner, William; Kuo, Ying-Hwa; Wu, Qian; Deng, Yue; Wang, Wenbin;

Published by: Journal of Atmospheric and Solar-Terrestrial Physics      Published on: 06/2013

YEAR: 2013     DOI: 10.1016/j.jastp.2013.03.009

Abel inversion; AURORA; COSMIC; Electron density; GNSS radio occultation; TIEGCM

Comparison of Joule heating associated with high-speed solar wind between different models and observations

Huang, Yanshi; Deng, Yue; Lei, Jiuhou; Ridley, Aaron; Lopez, Ramon; Allen, Robert; Butler, Brandon;

Published by: Journal of Atmospheric and Solar-Terrestrial Physics      Published on: Jan-02-2012

YEAR: 2012     DOI: 10.1016/j.jastp.2011.05.013

Anomalously low geomagnetic energy inputs during 2008 solar minimum

Deng, Yue; Huang, Yanshi; Solomon, Stan; Qian, Liying; Knipp, Delores; Weimer, Daniel; Wang, Jing-Song;

Published by: Journal of Geophysical Research      Published on: Jan-01-2012

YEAR: 2012     DOI: 10.1029/2012JA018039

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:

Energy input into the upper atmosphere associated with high-speed solar wind streams in 2005

Deng, Yue; Huang, Yanshi; Lei, Jiuhou; Ridley, Aaron; Lopez, Ramon; Thayer, Jeffrey;

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

YEAR: 2011     DOI: 10.1029/2010JA016201

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

Wind and temperature effects on thermosphere mass density response to the November 2004 geomagnetic storm

Lei, Jiuhou; Thayer, Jeffrey; Burns, Alan; Lu, Gang; Deng, Yue;

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

YEAR: 2010     DOI: 10.1029/2009JA014754

Reversed ionospheric convections during the November 2004 storm: Impact on the upper atmosphere

Using the Assimilative Mapping of Ionospheric Electrodynamics (AMIE) procedure, a particular period (2000–2350 UT on 9 November) in the November 2004 storm is studied. During this time interval, IMF Bz was strongly northward along with a high solar wind dynamic pressure, favorable conditions to form reversed convection in the polar region. Indeed, the AMIE outputs show strong reversed convection cells in both hemispheres for a long period (>1 h), which have rarely been observed. The impact on the thermospheric neutral wind has been investigated using the AMIE outputs as the electrodynamic inputs of the National Center for Atmospheric Research Thermosphere Ionosphere Electrodynamics General Circulation Model. After the ionospheric convection reversed, the neutral wind distribution at 400 km altitude changed correspondingly, and the difference wind patterns reversed in the polar cap region. By comparing the temporal variations of the difference ion convection and the difference neutral wind, it is found that horizontal neutral winds respond to the reversed convection with some time delay. The neutral wind response time (e-folding time) clearly has an altitudinal dependence varying from 45 min at 400 km altitude to almost 1.5 h at 200 km. The vertical component vorticity has a similar magnitude and distribution to previous studies in the northward Bz condition and changes the sign when the convection pattern is reversed. Comparison between the CHAMP observed cross-track wind and the simulated neutral wind exhibits a general agreement, and the temporal variations of CHAMP cross-track wind indicate a strong effect of the ion drag force on neutral winds.

Deng, Yue; Lu, Gang; Kwak, Young-Sil; Sutton, Eric; Forbes, Jeffrey; Solomon, Stan;

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

YEAR: 2009     DOI: https://doi.org/10.1029/2008JA013793

reversed convection; November 2004 storm

Contrasting Characteristics of the Thermospheric Composition and Density Response to the November 2004 Geomagnetic Storm

Lei, Jiuhou; Thayer, Jeffrey; Burns, Alan; Lu, Gang; Deng, Yue;

Published by: preparation for JGR      Published on:

YEAR: 2009     DOI:

The Global Ionosphere Thermosphere Model results of the April 2002 storm

Ridley, AJ; oth, G; Deng, Y; Kozyra, J; Immel, T; Paxton, L;

Published by:       Published on:

YEAR: 2004     DOI: