Statistical Study of the Relationship Between Ion Upflow and Field‐Aligned Current in the Topside Ionosphere for Both Hemispheres During Geomagnetic Disturbed and Quiet Time

Ma, Yuntao; Zhang, Qinghe; Jayachandran, P. T.; Oksavik, K.; Lyons, L. R.; Zou, Xing; Zhou, Shengjun; Hairston, M. R.; Wang, Yong

doi:10.1029/2019ja027538

Cited by 9 publications

(12 citation statements)

References 54 publications

(80 reference statements)

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“…We used the DMSP F17 satellite ionosphere measurements between 2014 and 2016, obtained from Madrigal Database. DMSP satellites operate in sun-synchronous near-polar orbits with an altitude of ∼850 km and an orbital period of about 101 min (Liu et al, 2018;Ma et al, 2018Ma et al, , 2020Zhang et al, 2020). Each satellite is equipped with three different space environment monitoring instruments.…”

Section: Methodsmentioning

confidence: 99%

“…Only the drift velocities designated as Quality Flag = 1 (the ion density is more than 10 3 cm −3 and the O + fraction is above 85%) are used in this study (C. Y. Huang et al, 2017;Ma et al, 2020).…”

Section: Methodsmentioning

confidence: 99%

“…The convection E is deduced from the ion drift velocity ( V ) measured by the SSIES monitor and the simultaneous in situ magnetic field ( B) obtained from SSM data at the spacecraft location through the equation of

\mathbf{E}=-\mathbf{V}\times \mathbf{B}

(Deng et al., 2015). Only the drift velocities designated as Quality Flag = 1 (the ion density is more than 10 3 cm −3 and the O + fraction is above 85%) are used in this study (C. Y. Huang et al., 2017; Ma et al., 2020).…”

Section: Methodsmentioning

confidence: 99%

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The Dawn–Dusk Asymmetrical Distribution of Earthward Poynting Flux in the Dayside Polar Cap From DMSP

et al. 2022

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We investigated the dawn–dusk asymmetrical distribution of quasi‐dc earthward Poynting flux (EPF) in the dayside polar cap of the Northern Hemisphere based on 3 years of observations at ∼850 km made by the Defense Meteorological Satellite Program (DMSP) F17. The satellite data have been sorted by low (Kp ≤ 2) and high (Kp > 2) geomagnetic activity, as well as the orientation and strength of interplanetary magnetic field (IMF) By and Bz components, binned by magnetic latitude, and magnetic local time. Statistical results show that the enhanced convection electric field favors the asymmetrical EPF distribution. Asymmetrical distribution characteristics are summarized as (a) there are mainly two enhanced EPF regions, near dawn and cusp and the mean EPF is 28% larger on the dawn than on the dusk for all IMF and Kp conditions. (b) The mean EPF for high Kp is 3 times greater than that for low Kp in the dayside polar cap. The enhanced EPF shifted from near the dawn for low Kp to near the cusp for high Kp. The EPF is also larger on the dawn than on the dusk for high Kp. (c) The EPF of the dayside polar cap is significantly enhanced as the IMF strength increases. Under IMF By+, EPF is greater on the dawn than on the dusk. The opposite is true under IMF By−. The IMF Bz− favors enhanced EPF and the EPF on the dawn (dusk) reaches its maximum for IMF By+ and Bz− (IMF By− and Bz−).

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

\mathbf{E}=-\mathbf{V}\times \mathbf{B}

Section: Methodsmentioning

confidence: 99%

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The Dawn–Dusk Asymmetrical Distribution of Earthward Poynting Flux in the Dayside Polar Cap From DMSP

et al. 2022

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“…The horizontal velocity is positive pointing sunward. The field-aligned current is calculated by dividing magnetic disturbance with satellite velocity, the details are described in Ma et al (2020). IMF Bz turns southward after 11:45 UT, and it is weak negative throughout the satellite transit.…”

Section: Event On 9 December 2015mentioning

confidence: 99%

A Comparative Study on the Hot Dense Plasma and Cold Patch by Using Multi‐Instrument Observations

Zhang

Lyons

et al. 2023

JGR Space Physics

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The polar cap hot patch is an enhanced density structure which is associated with particle precipitation, ion upflow and flow shears. Based on combined observations from DMSP satellites, EISCAT radar, and all‐sky imager at the Chinese Yellow River Station, the plasma characteristics and evolution of hot dense plasma and classical polar cap patch are investigated. Both of them show enhanced F region density, but the hot dense plasma is associated with higher electron temperature and enhanced E region electron density caused by particle precipitation. Compared to the cold patch, the hot dense plasma is closer to the cusp region and is associated with strong auroral emissions. Based on the joint observations, the evolution of the hot/cold dense plasma is discussed. In the initial phase the dense plasma comes from the sunlit lower latitude region, or from particle precipitation in the duskside auroral oval, and is heated locally by poleward moving auroral structures in the dayside auroral oval. Next the patches move poleward into the polar cap where a decaying electron temperature (i.e., less precipitation) gradually transform them into a cold patch.

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“…The cold patches are related to solar activity and found in the central polar cap (D. Zhang et al., 2021, 2022). The hot patches are found close to the auroral oval, associated with strong auroral emissions, ion upflows, and flow shears (e.g., Lorentzen et al., 2010; Ma et al., 2023; Nishimura et al., 2014; Zhang et al., 2023). The electron temperature of a hot patch may decrease to the same level as the ion temperature when the particle precipitation decreases, that is, it becomes a cold patch (Ma et al., 2023), which was obtained by analyzing two different patch events, rather than a complete evolution process of a patch.…”

Section: Introductionmentioning

confidence: 99%

Multi‐Instrument Observations of the Evolution of Polar Cap Patches Associated With Flow Shears and Particle Precipitation

Zhang,

Oksavik

et al. 2023

JGR Space Physics

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Simultaneous observations from Defense Meteorological Satellite Program, Swarm, Resolute Bay all‐sky imagers, GPS Total Electron Content and Super Dual Auroral Radar Network, are used to investigate the evolution and key characteristics of the Tongue of Ionization (TOI) being restructured into a polar cap patch. Six satellites crossed the TOI of patch as it moved from the dayside to the nightside. It was initially hot, then a mix of both cold and hot, and finally it became a cold patch. This suggests that cold patch is not only a result of solar extreme ultraviolet radiation, but may also develop when a hot patch cools down. Soft‐electron precipitation and flow shears both contribute to the TOI restructuring and the appearance of polar cap patch. The plasma density of patch at ∼500 km was at least 4 times higher than at ∼800 km. The plasma density enhancement gradually decreased as the patch evolved due to decreased production and transport of cold nightside low‐density plasma. Moreover, the duskward motion of the patch was influenced by changes in the ionospheric convection pattern.

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Statistical Study of the Relationship Between Ion Upflow and Field‐Aligned Current in the Topside Ionosphere for Both Hemispheres During Geomagnetic Disturbed and Quiet Time

Cited by 9 publications

References 54 publications

The Dawn–Dusk Asymmetrical Distribution of Earthward Poynting Flux in the Dayside Polar Cap From DMSP

The Dawn–Dusk Asymmetrical Distribution of Earthward Poynting Flux in the Dayside Polar Cap From DMSP

A Comparative Study on the Hot Dense Plasma and Cold Patch by Using Multi‐Instrument Observations

Multi‐Instrument Observations of the Evolution of Polar Cap Patches Associated With Flow Shears and Particle Precipitation

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