Magnetosphere–Ionosphere Conjugate Harang Discontinuity and Sub-Auroral Polarization Streams (SAPS) Phenomena Observed by Multipoint Satellites
It is well understood that near midnight, the Harang Discontinuity separates the auroral duskside eastward electrojet (EEJ) and dawnside westward electrojet (WEJ) and associated plasma flows driven by enhanced magnetospheric convections via Magnetosphere–Ionosphere (M–I) coupling. There are conflict...
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2024-12-01
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| author | Ildiko Horvath Brian C. Lovell |
| author_facet | Ildiko Horvath Brian C. Lovell |
| author_sort | Ildiko Horvath |
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| description | It is well understood that near midnight, the Harang Discontinuity separates the auroral duskside eastward electrojet (EEJ) and dawnside westward electrojet (WEJ) and associated plasma flows driven by enhanced magnetospheric convections via Magnetosphere–Ionosphere (M–I) coupling. There are conflicting reports regarding the significance of Region1 (R1) and R2 currents and the enhancement of Sub-Auroral Polarization Streams (SAPS) in the Harang region. We investigate the M–I conjugate Harang and SAPS phenomena using multipoint satellite observations. Results show the inner-magnetosphere (1) Harang region at midnight (between the plasmapause and the closed/open field-line boundary) with (2) a strong SAPS electric field (E<sub>X</sub> ≈ 30 mV/m; in magnitude) in a fast-time voltage generator (VG<sub>FT</sub>) near the plasmapause and the topside ionosphere (3) Harang Discontinuity (where R1 and R2 currents flow along) with (4) an enhanced SAPS flow (~1800 m/s) in the underlying VG<sub>FT</sub> system (requiring no R2 currents). From these (1–4) findings we conclude (i) the significance of both R1 and R2 currents in the observed M–I conjugate Harang phenomenon’s development, (ii) the different development of the reversing EEJ–WEJ compared to the regular auroral EEJ and WEJ in the topside ionosphere R1–R2 system, and (iii) the R2 currents’ absence in the enhanced SAPS flow newly formed in the VG<sub>FT</sub> system. |
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| institution | Kabale University |
| issn | 2073-4433 |
| language | English |
| publishDate | 2024-12-01 |
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| series | Atmosphere |
| spelling | doaj-art-d21841405379460ebefda8109a503f372024-12-27T14:09:49ZengMDPI AGAtmosphere2073-44332024-12-011512146210.3390/atmos15121462Magnetosphere–Ionosphere Conjugate Harang Discontinuity and Sub-Auroral Polarization Streams (SAPS) Phenomena Observed by Multipoint SatellitesIldiko Horvath0Brian C. Lovell1School of Electrical Engineering and Computer Science, The University of Queensland, St. Lucia, Brisbane, QLD 4072, AustraliaSchool of Electrical Engineering and Computer Science, The University of Queensland, St. Lucia, Brisbane, QLD 4072, AustraliaIt is well understood that near midnight, the Harang Discontinuity separates the auroral duskside eastward electrojet (EEJ) and dawnside westward electrojet (WEJ) and associated plasma flows driven by enhanced magnetospheric convections via Magnetosphere–Ionosphere (M–I) coupling. There are conflicting reports regarding the significance of Region1 (R1) and R2 currents and the enhancement of Sub-Auroral Polarization Streams (SAPS) in the Harang region. We investigate the M–I conjugate Harang and SAPS phenomena using multipoint satellite observations. Results show the inner-magnetosphere (1) Harang region at midnight (between the plasmapause and the closed/open field-line boundary) with (2) a strong SAPS electric field (E<sub>X</sub> ≈ 30 mV/m; in magnitude) in a fast-time voltage generator (VG<sub>FT</sub>) near the plasmapause and the topside ionosphere (3) Harang Discontinuity (where R1 and R2 currents flow along) with (4) an enhanced SAPS flow (~1800 m/s) in the underlying VG<sub>FT</sub> system (requiring no R2 currents). From these (1–4) findings we conclude (i) the significance of both R1 and R2 currents in the observed M–I conjugate Harang phenomenon’s development, (ii) the different development of the reversing EEJ–WEJ compared to the regular auroral EEJ and WEJ in the topside ionosphere R1–R2 system, and (iii) the R2 currents’ absence in the enhanced SAPS flow newly formed in the VG<sub>FT</sub> system.https://www.mdpi.com/2073-4433/15/12/1462plasmasphereupper atmosphereionospheremagnetosphere–ionosphere couplingenergy and particle transporthot zone |
| spellingShingle | Ildiko Horvath Brian C. Lovell Magnetosphere–Ionosphere Conjugate Harang Discontinuity and Sub-Auroral Polarization Streams (SAPS) Phenomena Observed by Multipoint Satellites Atmosphere plasmasphere upper atmosphere ionosphere magnetosphere–ionosphere coupling energy and particle transport hot zone |
| title | Magnetosphere–Ionosphere Conjugate Harang Discontinuity and Sub-Auroral Polarization Streams (SAPS) Phenomena Observed by Multipoint Satellites |
| title_full | Magnetosphere–Ionosphere Conjugate Harang Discontinuity and Sub-Auroral Polarization Streams (SAPS) Phenomena Observed by Multipoint Satellites |
| title_fullStr | Magnetosphere–Ionosphere Conjugate Harang Discontinuity and Sub-Auroral Polarization Streams (SAPS) Phenomena Observed by Multipoint Satellites |
| title_full_unstemmed | Magnetosphere–Ionosphere Conjugate Harang Discontinuity and Sub-Auroral Polarization Streams (SAPS) Phenomena Observed by Multipoint Satellites |
| title_short | Magnetosphere–Ionosphere Conjugate Harang Discontinuity and Sub-Auroral Polarization Streams (SAPS) Phenomena Observed by Multipoint Satellites |
| title_sort | magnetosphere ionosphere conjugate harang discontinuity and sub auroral polarization streams saps phenomena observed by multipoint satellites |
| topic | plasmasphere upper atmosphere ionosphere magnetosphere–ionosphere coupling energy and particle transport hot zone |
| url | https://www.mdpi.com/2073-4433/15/12/1462 |
| work_keys_str_mv | AT ildikohorvath magnetosphereionosphereconjugateharangdiscontinuityandsubauroralpolarizationstreamssapsphenomenaobservedbymultipointsatellites AT brianclovell magnetosphereionosphereconjugateharangdiscontinuityandsubauroralpolarizationstreamssapsphenomenaobservedbymultipointsatellites |