Bibliography

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

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:

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: