The occurrence of ionospheric signatures of plasmaspheric plumes over different longitudinal sectors

Abstract

Plasmaspheric plumes have ionospheric signatures and are observed as storm‐enhanced density (SED) in global positioning system (GPS) total electron content (TEC). These ionospheric signatures have been primarily observed over the American sector and in a few limited examples over the European sector. This study examines the longitudinal occurrence frequency of plasmaspheric plumes. We analyzed all images from the Imager for Magnetopause‐to‐Aurora Global Exploration (IMAGE) Extreme Ultraviolet Imager (EUV) databases for the first half of 2001 and identified a total of 31 distinct plume intervals observed during different storm events. Out of the total IMAGE EUV plumes that we identified, 12 were projected over North America, 10 over Asia, and the remaining 9 were over Europe and the Atlantic Ocean. Using ground‐based GPS TEC from MIT's Madrigal database, we searched for corresponding SED/TEC plumes at different longitudinal sector and found 12 ionospheric SED plume signatures over North America, 4 over Europe, and 2 over Asia. This indicates that the observation probability of an ionospheric SED plume when a plasmaspheric plume is seen is 100% in the American sector, 50% in the European sector, and 20% in the Asian sector. This could be due to the fact that the plumes may be either positioned beyond the limit of the ground‐based GPS field of view, which happens mainly when there is less plasmaspheric erosion, or are too weak to be detected by the sparse number of GPS receivers over Asia. The in situ plasma densities from the available coincident defense metrological satellite program (DMSP) satellites were also used to study the characteristics of SED/TEC plume at DMSP orbiting altitude (i.e., ∼870 km). The TOPographic EXplorer (TOPEX) altimeter TEC also is used to identify the conjugate SED/plume signature over the Southern Hemisphere.

Plasmaspheric Density Structures and Dynamics: Properties Observed by the CLUSTER and IMAGE Missions

“…TEC signatures of plumes are more common in the North American sector, though weaker plume signatures are seen over Europe and Asia (Yizengaw et al 2008). It has been demonstrated that plumes play a crucial role in midlatitude ionospheric density enhancements (Yizengaw et al 2006), polar ionization patches (Su et al 2001) and are strongly correlated with the loss of ring current ions (Burch et al 2001b).…”

“…These effects are especially pronounced over the Americas and Foster et al (2005) suggested that this results from a strengthening of the equatorial ion fountain due to electric fields in the vicinity of the South Atlantic Anomaly. Yizengaw et al (2008) demonstrated that EUV observes plumes at all longitudes, but that TEC signatures of plumes are more common in the North American sector, though weaker plume signatures are seen over Europe and Asia. This study and many earlier demonstrate that plumes are most often observed in the aftermath of enhanced geomagnetic activity (not just geomagnetic storms as defined by some minimum Dst value) and that they tend to ap- pear at earlier LT with an increase of geomagnetic activity.…”

Temporal and Spatial Variations of Storm Time Midlatitude Ionospheric Trough Based on Global GNSS‐TEC and Arase Satellite Observations

“…The development is caused by the injection of plasmasheet particles into the inner magnetosphere associated with an enhanced convection electric field in the magnetosphere via a reconnection process between the southward interplanetary magnetic field (IMF) and Earth's magnetic field (e.g., Tsurutani et al, ). The enhanced convection electric field leads to a dramatic effect on the dynamics of the ionosphere and plasmasphere such as the formation of a plasmaspheric plume (e.g., Goldstein & Sandel, ; Moldwin et al, ; Yizengaw et al, ) and its ionospheric signature (e.g., Foster et al, , ; Foster & Rideout, ; Yizengaw et al, , ). The convection electric field produces a plasma density enhancement in the ionosphere with a narrow structure which is named storm‐enhanced density (SED; Foster, ).…”

Remote sensing the plasmasphere, plasmapause, plumes and other features using ground-based magnetometers

“…The high-altitude plasmapause maps to the equatorward edge of the mid-latitude ionospheric trough (Foster et al 1978;Yizengaw & Moldwin 2005). Enhanced storm-time density structures are monitored by GPS total electron content (TEC) techniques and incoherent scatter radars and are the low altitude signatures of drainage plumes (Foster et al 2002;Yizengaw et al 2008).…”