The Ion/Electron Temperature Characteristics of Polar Cap Classical and Hot Patches and Their Influence on Ion Upflow

Ma, Yuntao; Zhang, Qinghe; Zou, Xing; Heelis, R. A.; Oksavik, K.; Wang, Yong

doi:10.1029/2018gl079099

Cited by 23 publications

(47 citation statements)

References 31 publications

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“…The lack of E y lobe structures in Case 3 also indicates that the patch is moving more slowly than the patches in Cases 1 and 2, which is not just consistent with imager data but also indicates a lack of enhanced ionospheric flow channels. These findings are consistent with Ma et al (), who show that patches closer to their initial creation phase are more likely to be associated with particle precipitation and plasma flows.…”

Section: Resultssupporting

confidence: 93%

“…Meanwhile, Case 3 features a patch that drifts much slower and is dissipating in luminosity and disappearing, which means that the patch is relatively old. Since Case 3 shows no significant enhancements in E x , E y , FACs, electron flux, or ion flux, these results indicate that the magnetospheric structures on the patch field lines are physically connected to the patch motion and that MI coupling structures observed in the lobe are the strongest when the patch propagates faster or when the patch is younger, as is consistent with Ma et al ().…”

Section: Discussionsupporting

confidence: 87%

“…Zhang et al () suggests that since hot polar cap patches can have the same order of density enhancement as classical polar cap patches, they may be produced by dayside photoionized plasma being transported into polar cap flow channels. Statistical results from Ma et al () indicate that hot polar cap patches have higher convection speeds and stronger FACs, while the classical polar cap patches in the central polar cap generally show lower convection speeds and weaker FACs. Their work suggests that hot polar cap patches are associated with the initial creation phase of polar cap patches and are associated with particle precipitation and bursty plasma flow, while the classical polar cap patches are more mature.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Mesoscale Convection Structures Associated With Airglow Patches Characterized Using Cluster‐Imager Conjunctions

et al. 2019

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Polar cap ionospheric plasma flow studies often focus on large‐scale averaged properties and neglect the mesoscale component. However, recent studies have shown that mesoscale flows are often found to be collocated with airglow patches. These mesoscale flows are typically a few hundred meters per second faster than the large‐scale background and are associated with major auroral intensifications when they reach the poleward boundary of the nightside auroral oval. Patches often also contain ionospheric signatures of enhanced field‐aligned currents and localized electron flux enhancements, indicating that patches are associated with magnetosphere‐ionosphere coupling on open field lines. However, magnetospheric measurements of this coupling are lacking, and it has not been understood what the magnetospheric signatures of patches on open field lines are. The work presented here explores the magnetospheric counterpart of patches and the role these structures have in plasma transport across the open field‐line region in the magnetosphere. Using red‐line emission measurements from the Resolute Bay Optical Mesosphere Thermosphere Imager, and magnetospheric measurements made by the Cluster spacecraft, conjugate events from 2005 to 2009 show that lobe measurements on field lines connected to patches display (1) electric field enhancements, (2) Region 1 sense field‐aligned currents, (3) field‐aligned enhancements in soft electron flux, (4) downward Poynting fluxes, and (5) in some cases enhancements in ion flux, including ion outflows. These observations indicate that patches highlight a localized fast flow channel system that is driven by the magnetosphere and propagates from the dayside to the nightside, most likely being initiated by enhanced localized dayside reconnection.

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Section: Resultssupporting

confidence: 93%

Section: Discussionsupporting

confidence: 87%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Mesoscale Convection Structures Associated With Airglow Patches Characterized Using Cluster‐Imager Conjunctions

et al. 2019

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“…(2017) and Ma et al. (2018). We intended to remove contributions of such patches to the statistics by using an additional density threshold in the PCPDA algorithm of Spicher et al.…”

Section: Discussionmentioning

confidence: 96%

Occurrence Distribution of Polar Cap Patches: Dependences on UT, Season and Hemisphere

et al. 2021

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Polar cap patches are islands of enhanced electron density in the polar cap F region ionosphere, which sometimes affect the propagation of trans‐ionospheric radio waves. Considering the intake of daytime sunlit plasma by the high‐latitude convection as the primary cause of patches, the spatial overlap between the convection and the daytime sunlit plasma should be one of the critical factors controlling the generation of patches. To confirm this hypothesis, we statistically investigated the UT and seasonal distributions of patch occurrence frequency in both the hemispheres by using in situ plasma density data from the Swarm satellite. As a result, it was found that the occurrence distribution of patches is a complex function of UT, season and hemisphere, but it can be mostly interpreted by the spatial overlap between the high‐latitude convection and the solar terminator. This suggests that polar cap patches are not necessarily phenomena that occur only during winter months. That is, patches can often be observed even in periods away from the winter solstice if the location of solar terminator in the magnetic coordinate system is appropriate for the generation of patches. For example, in the southern hemisphere, where the offset between the geographic and magnetic poles is larger than that in the northern hemisphere, the highest patch occurrence rate is obtained around the equinoctial periods. These results indicate that it is needed to take these dependences into account when we discuss and predict the space weather impacts of patches on the trans‐ionospheric radio propagation.

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“…Ma YZ et al (2018b) investigated the characteristics of hot patches versus classical patches by using a five‐year database of in situ plasma observations from DMSP satellites. The vertical ion flux is generally downward in classical patches ( T i / T e > 0.8 or T e < T i + 600 K), and generally upward in hot patches ( T i / T e < 0.8 or T e > T i + 600 K).…”

Section: Ionospheric Irregularity and Scintillationmentioning

confidence: 99%

Recent ionospheric investigations in China (2018–2019)

Liu

Wan

2020

Earth and Planetary Physics

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Key Points:Ionospheric observations have continuously accumulated with increasing GNSS receivers being installed q Studies of ionospheric climatology and space weather highlight new physical understanding q Study of ionospheric irregularities/scintillations reports interesting features q Abstract: Since the release of the 2018 National Report of China on ionospheric research ( Liu LB and Wan WX, 2018) to the Committee on Space Research (COSPAR), scientists from Mainland China have made many new fruitful investigations of various ionospheric-related issues. In this update report, we briefly introduce more than 130 recent reports ( [2018][2019]. The current report covers the following topics: ionospheric space weather, ionospheric structures and climatology, ionospheric dynamics and couplings, ionospheric irregularity and scintillation, modeling and data assimilation, and radio wave propagation in the ionosphere and sounding techniques. ΔV para (m/s) SYM-H (nT) V para (m/s) V para (m/s) ΔV para (m/s) Figure 2. (a) The SYM-H index on 13-17 July 2012. The blue line marks the storm onset (at 06:42 UT on 15 July); yellow and gray areas indicate the 24-hour storm-time and 24-hour quiet-time intervals. (b) The blue dots denote the storm-time equatorial field-aligned plasma drifts observed by C/NOFS with red curve representing median and red lines denoting upper and lower quartile values. (c) Same as panel (b), but for the 24-hour quiet time interval. (d) The difference between (b) and (c). (e-h) Same as panels (a-d), but for the case on 7-11 July 2012 where the 24-hour quiet and storm intervals start at 04:12 UT on 7 and 9 July, respectively, after Zhang R et al. (2018). Earth and Planetary Physics

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The Ion/Electron Temperature Characteristics of Polar Cap Classical and Hot Patches and Their Influence on Ion Upflow

Cited by 23 publications

References 31 publications

Mesoscale Convection Structures Associated With Airglow Patches Characterized Using Cluster‐Imager Conjunctions

Mesoscale Convection Structures Associated With Airglow Patches Characterized Using Cluster‐Imager Conjunctions

Occurrence Distribution of Polar Cap Patches: Dependences on UT, Season and Hemisphere

Recent ionospheric investigations in China (2018–2019)

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