Bibliography

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:

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

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

Statistical relationship between large-scale upward field-aligned currents and electron precipitation

Simultaneous observations of Birkeland currents by the constellation of Iridium satellites and N2 Lyman\textendashBirge\textendashHopfield (LBH) auroral emissions measured by the Global Ultraviolet Imager (GUVI) onboard the Thermosphere, Ionosphere, and Mesosphere Energetics and Dynamics (TIMED) satellite are used to establish relationships between large-scale upward field-aligned currents and electron precipitation during stable current configurations. The electron precipitation was inferred from GUVI data using a statistical relationship between LBH intensity and electron energy flux. LBH emissions with \>5\% contribution from protons, identified by Lyman-alpha intensity, were excluded from the analysis. The Birkeland currents were derived with a spatial resolution of 3\textdegree in latitude and 2 h in local time. For southward interplanetary magnetic field (IMF), the electron precipitation occurred primarily within and near large-scale upward currents. The correspondence was less evident for northward IMF, presumably because the spatial variability is large compared to the areas of interest so that the number of events identified is smaller and the derived statistical distributions are less reliable. At dusk, the correlation between upward current and precipitation was especially high, where a larger fraction of the electron precipitation is accelerated downward by a field-aligned potential difference. Unaccelerated electron precipitation dominated in the morning sector, presumably induced by scattering of eastward-drifting energetic electrons into the loss cone through interaction with whistler-mode waves (diffuse precipitation) rather than by field-aligned acceleration. In the upward Region 1 on the dayside, where electron precipitation is almost exclusively due to field-aligned acceleration, a quadratic relationship between current density and electron energy flux was observed, implying a linear current\textendashvoltage relationship in this region. Current density and electron energy flux in the regions of the large-scale upward currents from pre-midnight through dawn to noon are essentially uncorrelated consistent with a dominance of diffuse electron precipitation to the incident energy flux.

Korth, Haje; Zhang, Yongliang; Anderson, Brian; Sotirelis, Thomas; Waters, Colin;

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

YEAR: 2014     DOI: 10.1002/2014JA019961

Birkeland Currents; Auroral Emissions; electron precipitation; Current-Precipitation Relationship; Current-Voltage Relationship

Operational Space Weather Needs-Perspectives from SEASONS 2014

Comberiate, Joseph; Kelly, MA; Paxton, Larry; Schaefer, Robert; Bust, Gary; Sotirelis, Thomas; Fox, Nicola;

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:

The evolving space weather system—Van Allen Probes contribution

Zanetti, LJ; Mauk, BH; Fox, NJ; Barnes, RJ; Weiss, M; Sotirelis, TS; Raouafi, N-E; Kessel, RL; Becker, HN;

Published by: Space Weather      Published on:

YEAR: 2014     DOI:

Empirical relationship between electron precipitation and far-ultraviolet auroral emissions from DMSP observations

Auroral emissions observed in the far-ultraviolet wavelength range are compared with measurements of the coincident precipitating electrons and ions that produce the emissions in a large-scale correlative study. The auroral emissions and particle precipitation are observed with the Special Sensor Ultraviolet Spectrographic Imager and SSJ5 detectors, respectively, both onboard the DMSP F16 satellite. Coincident observations along the same magnetic field line in the Northern Hemisphere are assembled from two consecutive winters (during 2005\textendash2007). A numerical fit to 27,922 coincident observations provides an empirical relationship between the electron energy flux and the intensity of Lyman-Birge-Hopfield long emissions, J_Ee = 4.90 .10⁸ (eV s^\textendash1 sr^\textendash1 cm^\textendash2)/R I_LBHL (valid in the absence of significant ion fluxes: J_Ee \> 10 J_Eion). A fit to 1308 coincident observations provides the relationship between the average electron energy and the Lyman-Birge-Hopfield short to Lyman-Birge-Hopfield long emission ratio, \<E_e \> = 19.6 keV exp(\textendash2.34 I_LBHS / I_LBHL) (valid from 3 to 19.6 keV). These resulting empirical relationships permit the energy flux and average energy of precipitating electrons to be inferred from far-ultraviolet imagery, in the absence of significant ion precipitation.

Sotirelis, Thomas; Korth, Haje; Hsieh, Syau-Yun; Zhang, Yongliang; Morrison, Daniel; Paxton, Larry;

Published by: Journal of Geophysical Research: Space Physics      Published on: 03/2013

YEAR: 2013     DOI: 10.1002/jgra.50157

DMSP; electron aurora; electron precipitation; FUV Aurora

Empirical Relationship Between LBH Auroral Emissions and Particle Precipitation

Hsieh, SW; Sotirelis, T; Korth, H; Zhang, Y; Paxton, LJ;

Published by:       Published on:

YEAR: 2011     DOI:

Predictive ability of four auroral precipitation models as evaluated using Polar UVI global images

Newell, P.; Sotirelis, T.; Liou, K.; Lee, A.; Wing, S.; Green, J.; Redmon, R.;

Published by: Space Weather      Published on: Jan-01-2010

YEAR: 2010     DOI: 10.1029/2010SW000604

Lower Atmosphere Wave Effects on Ionospheric Variability

Talaat, Elsayed; Yee, Jeng-Hwa; Paxton, Larry; DeMajistre, Robert; Christensen, Andrew; Mlynczak, MG; , Russell; Zhu, Xun; Sotirelis, Thomas; Kil, Hyosub;

Published by: 37th COSPAR Scientific Assembly      Published on:

YEAR: 2008     DOI:

The linkage between the ring current and the ionosphere system

The coupling between the ring current and the ionosphere is briefly reviewed and discussed. Given global energetic neutral atom (ENA) observations of the ring current, the three-dimensional current system driven by ring current plasma pressure (the region 2 system) is derived to illustrate where the ring current connects to the ionosphere. Special attention is given to how the ring current and ionospheric conductance set up the sub-auroral polarization streams (SAPS) through the closure of the region 2 current through the ionospheric trough region.

Brandt, PC; Zheng, Y; Sotirelis, TS; Oksavik, K; Rich, FJ;

Published by: Midlatitude ionospheric dynamics and disturbances, edited by: Kintner, PM, Coster, AJ, Fuller-Rowell, T., Mannucci, A. J., Mendillo, M., and Heelis, R., Geophys. Monog. Series      Published on:

YEAR: 2008     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:

The effects of solar activity on the low-latitude ionosphere as observed from space

Talaat, ER; Yee, J-H; DeMajistre, R; Paxton, LJ; Christensen, A; Sotirelis, T; Smith, DC; Bilitza, D;

Published by:       Published on:

YEAR: 2006     DOI:

Lower Atmosphere Effects on Thermospheric and Ionospheric Variability

Talaat, ER; Yee, J; Paxton, L; DeMajistre, R; Christensen, A; Russell, J; Mlynczak, M; Zhu, X; Sotirelis, T; Smith, D;

Published by:       Published on:

YEAR: 2006     DOI:

The climatology of the quiet nighttime low-latitude ionosphere

Talaat, ER; Yee, J; DeMajistre, R; Paxton, L; Kil, H; Zhang, Y; Sotirelis, T; Christensen, A; Palo, S; Azeem, I; , others;

Published by:       Published on:

YEAR: 2005     DOI:

Dynamics of the Auroral and State of the Magnetosphere During Storms of April, 2002: DMSP and TIMED/GUVI Observations

Meng, CI; Zhang, Y; Paxton, LJ; Newell, PT; Sotirelis, TS; Christensen, AB;

Published by:       Published on:

YEAR: 2002     DOI: