Global‐scale observations of ionospheric convection variation in response to sudden increases in the solar wind dynamic pressure

Gillies, D. M.; St.-Maurice, J.-P.; McWilliams, K. A.; Milan, S. E.

doi:10.1029/2011ja017255

Cited by 14 publications

(35 citation statements)

References 44 publications

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“…Besides the geomagnetic field observations, the Super Dual Auroral Radar Network (SuperDARN) (Greenwald et al 1995) has played an important role in the measurement of the two-dimensional structure of ionospheric convection associated with SIs (Lyatsky et al 1999;Thorolfsson et al 2001;Vontrat-Reberac et al 2002;Coco et al 2008;Huang et al 2008;Kane and Makarevich 2010;Liu et al 2011;Gillies et al 2012;Hori et al 2012). A conclusion from these studies with the radar observations is that changes in flow direction and the polarity of flow shear are consistent with a PI-MI sequence on ground magnetograms described by the SC model proposed by Araki (1977Araki ( , 1994.…”

Section: Introductionsupporting

confidence: 60%

IMF-By dependence of transient ionospheric flow perturbation associated with sudden impulses: SuperDARN observations

Hori

Shinbori

Fujita³

et al. 2015

Earth Planet Sp

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A statistical study using a large dataset of Super Dual Auroral Radar Network (SuperDARN) observations is conducted for transient ionospheric plasma flows associated with sudden impulses (SI) recorded on ground magnetic field. The global structure of twin vortex-like ionospheric flows is found to be consistent with the twin vortices of ionospheric Hall current deduced by the past geomagnetic field observations. An interesting feature, which is focused on in this study, is that the flow structures show a dawn-dusk asymmetry depending on the combination of the polarity of SI and interplanetary magnetic field (IMF)-By. Detailed statistics of the SuperDARN observations reveal that the dawn-dusk asymmetry of flow vortices due to IMF-By appears during negative SIs, while such asymmetric characteristics are not seen during positive SIs. On the basis of the upstream observations, we suggest that this particular dawn-dusk asymmetry is caused by the interaction between the pre-existing round convection cell and a pair of the transient convection vortices associated with SIs.

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Section: Introductionsupporting

confidence: 60%

IMF-By dependence of transient ionospheric flow perturbation associated with sudden impulses: SuperDARN observations

Hori

Shinbori

Fujita³

et al. 2015

Earth Planet Sp

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“…As the strength of the enhancement increases, dB/dt and the magnitude of the maximum depression successively increase, whereas the time to reach the maximum depression decreases. The averaged SYM‐H trace for the strongest event classification in this study agrees with the notion that a large SSC is a prerequisite for the occurrence of magnetic storms [for example, as demonstrated in Gillies et al ., ]; the strongest storms (maximum average depression of −51 nT) occur after the largest change in the SYM‐H index at the time of SC onset (36 nT).…”

Section: Resultsmentioning

confidence: 99%

Assessment of GIC risk due to geomagnetic sudden commencements and identification of the current systems responsible

2014

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During periods of enhanced geomagnetic activity, geomagnetically induced currents (GIC) flow in power systems potentially causing damage to system components or failure of the system. The largest GIC are produced when there are large rates of change of the geomagnetic field (dB/dt). It is well established that the main phase of a geomagnetic storm, particularly the magnetic substorms occurring during that period, is a cause of large GIC and hence a risk factor for power systems. However, some power system disturbances have been associated with the occurrence of a storm sudden commencement (SSC) prior to the main phase. We investigate the magnetic signature observed on the ground and the associated solar wind and interplanetary magnetic field (IMF) conditions for both SSC and sudden impulse (SI) events, which are grouped together as sudden commencements (SC). SCs are primarily attributed to a sudden enhancement of the magnetopause current. For some events, we show that there is a high-latitude enhancement (HLE) of the SC amplitude and corresponding dB/dt. The limited spatial extent suggests an ionospheric current source. Examination of the polarity of the change in the X-component magnetic field shows that the HLE is due to a sudden increase of the ionospheric convection electrojets. The occurrence of the HLE is more prevalent for SSC-type SCs, SCs caused by coronal mass ejections as opposed to corotating interaction regions, and SCs associated with a large solar wind speed (v sw ) prior to the SC or a large Δv sw at the time of the SC.

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“…This interaction becomes more active when the solar wind dynamic pressure pulse encounters the magnetosphere. Special atten tion is paid to the growth of the magnetospheric mag netic field just after such encounter (e.g., Borodkova et al, 2006;Gillies et al, 2012;Belenkaya et al, 2014). Borodkova et al (2006) stated that a maximum magnetospheric magnetic field disturbance occurs near the noon.…”

Section: Introductionmentioning

confidence: 99%

“…Borodkova et al (2006) stated that a maximum magnetospheric magnetic field disturbance occurs near the noon. The second significant effect of the magnetosphere ionosphere perturbation is a sharp decrease of the polar cap area (e.g., Zesta et al, 2000;Boudouridis et al, 2003Boudouridis et al, , 2005Ngwira et al, 2012;Gillies et al, 2012) simultaneously with intensifica tion of the auroral zone. The solar wind pressure jump leads to the particle precipitation into the cusp region (e.g., Cerisier et al, 2005).…”

Section: Introductionmentioning

confidence: 99%

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Polar cap response to the solar wind density jump under constant southward IMF

Калегаев

Blokhina

2014

Geomagn. Aeron.

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Sharp changes of the solar wind parameters determining the dynamic pressure jump lead to strong magnetosphere ionosphere disturbances. Here the effect on the Earth's ionospheric high latitudes of the solar wind dynamic pressure pulse caused only by the increase of the interplanetary plasma density under southward constant IMF is considered. We investigate reaction of the cross polar cap potential on the increase of AL index and/or jump of the solar wind density. It is found that for the case of 10 January 1997 the main contribution to the polar cap potential drop increase gave the growth of AL index relative to the input of the solar wind density jump. We also study the influence of the solar wind density increase on the cross polar cap potential for the quiet magnetospheric conditions. It occurred that the polar cap potential differ ence decreases with the great increase of the interplanetary plasma density. For the disturbed magnetosphere the main role in the polar cap potential drop increase plays increase of AL. Thus, we found the change of the cross polar cap potential due to the AL index variations and/or the solar wind density drop even in a case when the interplanetary electric field is constant.

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Global‐scale observations of ionospheric convection variation in response to sudden increases in the solar wind dynamic pressure

Cited by 14 publications

References 44 publications

IMF-By dependence of transient ionospheric flow perturbation associated with sudden impulses: SuperDARN observations

IMF-By dependence of transient ionospheric flow perturbation associated with sudden impulses: SuperDARN observations

Assessment of GIC risk due to geomagnetic sudden commencements and identification of the current systems responsible

Polar cap response to the solar wind density jump under constant southward IMF

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