On the direction of the Poynting flux associated with equatorial plasma depletions as derived from Swarm

Abstract

Magnetic and electric field observations from the European Space Agency Swarm mission are used to report the direction of electromagnetic energy flux associated with equatorial plasma depletions. Contrary to expectations, the observations suggest a general interhemispheric Poynting flux rather than concurrent flows at both hemispheres toward or away from the equator. Of high interest is a particular behavior noticed over the region with the largest variation in the magnetic declination. This is a Poynting flux flowing mainly into the southern magnetic hemisphere about between 60°W and 30°E and into the northern magnetic hemisphere between 110°W and 60°W. The abrupt change in the flow direction at 60°W is suggested to be caused by an asymmetry between the hemispheres on the ionospheric conductivity, likely due to the influence of thermospheric winds and the presence of the South Atlantic Anomaly.

Ion Velocity and Temperature Variation Around Topside Nighttime Irregularities: Contrast Between Low‐ and Mid‐Latitude Regions

“…(2014, Figure 8), and Rodriguez‐Zuluaga et al. (2017, Summary).…”

Statistical Analysis of Equatorial Plasma Irregularities Retrieved From Swarm 2013–2019 Observations

“…Statistical studies have been conducted to understand the occurrence probability of EPIs as a function of local time, latitude, longitude, season, solar cycle, and geomagnetic variation. Much has been done by using long‐term continuous observations, such as ground‐based GNSS receivers and space‐based radio occultation measurements (Carter et al, ; Nishioka et al, ; Yu et al, ), measurements of retarding potential analyzer onboard Atmosphere Explorer‐E (AE‐E) satellite (Kil & Heelis, ), plasma density detected by ion sensor onboard the Defense Meteorological Satellite Program (DMSP) (Burke, Gentile, et al, ; Burke, Huang, et al, ; Gentile et al, ; Huang et al, ), observations of the Ion Trap sensor onboard FORMASAT‐1 satellite (Su et al, , ; Kil, Paxton, et al, ), measurements of the Ion Velocity Meter (IVM) or Planar Langmuir Probe onboard the Communications/Navigation Outage Forecasting System (C/NOFS) satellite (Huang et al, ; Retterer & Roddy, ; Smith & Heelis, ; Yizengaw et al, ), flux‐gate magnetometer measurements onboard CHAMP satellite (Lühr et al, ; Stolle et al, ), and electric field instrument (EFI) measurements onboard Swarm constellation (Rodríguez‐Zuluaga et al, ; Wan et al, ; Xiong et al, , ; Zakharenkova et al, ).…”

Diagnosing low-/mid-latitude ionospheric currents using platform magnetometers: CryoSat-2 and GRACE-FO

“…Also, there are other ionospheric current systems with weaker magnetic effect than the two mentioned above. To name a few, we have solar quiet (Sq) currents flowing in the ionospheric E-layer (Yamazaki and Maute 2017), inter-hemispheric field-aligned currents (IHFACs) connecting the two Sq systems in respective hemispheres (Shinbori et al 2017;Lühr et al 2015Lühr et al , 2019, gravity-driven horizontal currents (Lühr and Maus 2006;Maute and Richmond 2017), pressure-driven currents which counter-balance plasma density inhomogeneity (Lühr et al 2003;Stolle et al 2006;Alken et al 2016;Maute and Richmond 2017;Rodríguez-Zuluaga et al 2019;Laundal et al 2019), wind-driven dynamo currents flowing vertically in the ionospheric F-layer (Lühr and Maus 2006), horizontal currents across the polar cap closing net auroral FACs (Lühr and Zhou 2020, and references therein), and low-/mid-latitude small-scale FACs resulting from a divergence of background currents by ionospheric irregularities (Park et al 2009;Rodríguez-Zuluaga et al 2017;Yin et al 2019). There also exist magneto-hydrodynamic (MHD) waves propagating in the ionosphere and accompanying currents, such as Pc3 (Heilig and Sutcliffe 2016) and Pc1 pulsations (Kim et al 2018;Gou et al 2020).…”