Stimulation of plasma waves in the magnetosphere using satellite JIKIKEN (EXOS-B). Part II. Plasma Density across the plasmapause.

Oya, Hiroshi; Ono, Takayuki

doi:10.5636/jgg.39.591

Cited by 22 publications

(5 citation statements)

References 37 publications

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“…The plasmapause is formed at the location of counteraction of corotation and dawn‐to‐dusk convection electric fields in the magnetosphere (Nishida, 1966). Therefore, because the counteraction region moves toward the Earth with day‐night and dawn‐dusk asymmetries when the dawn‐to‐dusk convection electric field becomes strong, the plasmapause also moves toward the Earth during a significant enhancement of the convection electric field associated with geomagnetic disturbances such as a geomagnetic storm (e.g., Chappell et al., 1970; Oya & Ono, 1987; Shinbori et al., 2005). In this period, the region of high‐dense plasma is formed in the magnetosphere of the noon‐afternoon sectors beyond the plasmasphere, and this has been called plasmaspheric tail (Chappell, 1975) or plume (Ober et al., 1997).…”

Section: Introductionmentioning

confidence: 99%

Relationship Between the Locations of the Midlatitude Trough and Plasmapause Using GNSS‐TEC and Arase Satellite Observation Data

et al. 2021

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The midlatitude trough is characterized by a significant plasma depletion in the F-region of the ionosphere at subauroral and midlatitudes below the auroral oval. The structure of the midlatitude trough shows a Abstract Relationship between the locations of the midlatitude trough minimum in the ionosphere and plasmapause in the inner magnetosphere has been statistically investigated using global navigation satellite system (GNSS)-total electron content (TEC) and electron density data obtained from the Arase satellite from March 23, 2017 to May 31, 2020. In this analysis, we identify the midlatitude trough minimum as a minimum value of GNSS-TEC at subauroral and midlatitude regions, and determine the plasmapause as an electron density decrease by a factor of 5 or more within ΔL < 0.5 in the inner magnetosphere. As a result, the plasmapause does not always coincide with the midlatitude trough minimum in all magnetic local time (MLT) sectors under all geomagnetic conditions. During the geomagnetically quiet periods, the midlatitude trough minimum is located at higher and lower geomagnetic latitudes (GMLATs) of the plasmapause in the MLT ranges of 5-21 and 21-5 h, respectively. This implies that both the features could not be on the same magnetic field line. On the other hand, during the storm main phase, the midlatitude trough minimum and plasmapause move toward a low-latitude region with day-night and dawn-dusk asymmetries and the correlation becomes highest, compared with that under other geomagnetic conditions. Especially, both the features mapped on the ionosphere at a height of 300 km exist near GMLAT in the afternoon-midnight sectors. This suggests that the midlatitude trough and plasmapause are formed at almost the same location due to an enhanced subauroral polarization stream during the storm main phase.Plain Language Summary The Earth's plasmasphere, which is filled with dense cold plasmas originating from the ionosphere, has a donut-like structure in the inner magnetosphere. The plasma density decreases gradually with an increasing distance from the topside ionosphere, and it decreases sharply around the plasmapause. The location of the plasmapause tends to move toward the Earth when the geomagnetic activity increases due to the arrival of solar wind disturbances to the magnetosphere. Furthermore, the plasmaspheric plasmas give major influence on plasma wave propagation, generation, absorption, and wave-particle interaction. Therefore, to investigate the shape of the plasmasphere and the spatial distribution of plasma density is important for understanding the generation processes of high-energetic particles in the inner magnetosphere. On the other hand, it has been thought that the midlatitude trough indicating the plasma density depletion in the ionosphere with a narrow latitudinal structure corresponds to the location of the plasmapause. In this study, we investigate the relationship between the locations of the midlatitude trough minimum in the ionosphere and plasmapause in the inner magnetosphere usi...

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Section: Introductionmentioning

confidence: 99%

Relationship Between the Locations of the Midlatitude Trough and Plasmapause Using GNSS‐TEC and Arase Satellite Observation Data

et al. 2021

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“…The fluctuations in the electron density were observed since the beginning of the in situ observations. One of the earliest in situ observations of the cold plasma density was made by OGO 5 (Chappell et al., 1970), EXOS‐B (Oya & Ono, 1987), CRRES (LeDocq et al., 1994), and Los Alamos National Laboratory (Moldwin et al., 1995) satellite missions. These observations revealed the existence of density irregularities near the plasmapause and the outer regions of the plasmasphere.…”

Section: Introductionmentioning

confidence: 99%

Investigation of Small‐Scale Electron Density Irregularities Observed by the Arase and Van Allen Probes Satellites Inside and Outside the Plasmasphere

et al. 2021

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The plasmasphere is the innermost region of the Earth's magnetosphere, which is filled with cold (low energy ∼1-10 electron volt (eV) and dense (10-10 4 cm −3)) plasma of ionospheric origin trapped to the Earth's magnetic field, forming a thermal plasma cloud encircling the Earth (Darrouzet et al., 2009b; Lemaire et al., 1998). Outside the plasmasphere, the plasma characteristics change abruptly to tenuous (1 cm −3), hot (high energy ∼100 eV) plasma. The boundary that separates this outer region of the highly energized, low-density plasma from the plasmasphere, is called plasmapause. The plasma motions in the inner magnetosphere are dominated by large scale electric fields. The corotation electric field enforces the corotation of cold plasma near the Earth, and the magnetospheric convection electric field (generated by the interaction between the solar wind and the magnetosphere) causes the loss of cold plasma outside the plasmasphere. The convection electric field, being a key factor for the formation of the plasmapause (Pierrard et al., 2008), the location and sharpness of the plasmapause vary with

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“…These works are particularly important in light of the evidence that the plasmapause density profile becomes highly structured in the aftermath of disturbances and during extended recovery periods (e.g. Oya and Ono, 1987;Koons, 1989;Horwitz et al, 1990;Carpenter et al, 1993Carpenter et al, , 2000Moldwin et al, 1995).…”

Section: Examples Of Research On the Pblmentioning

confidence: 99%

The Plasmasphere Boundary Layer

2004

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Abstract.As an inner magnetospheric phenomenon the plasmapause region is of interest for a number of reasons, one being the occurrence there of geophysically important interactions between the plasmas of the hot plasma sheet and of the cool plasmasphere. There is a need for a conceptual framework within which to examine and discuss these interactions and their consequences, and we therefore suggest that the plasmapause region be called the Plasmasphere Boundary Layer, or PBL. Such a term has been slow to emerge because of the complexity and variability of the plasma populations that can exist near the plasmapause and because of the variety of criteria used to identify the plasmapause in experimental data. Furthermore, and quite importantly in our view, a substantial obstacle to the consideration of the plasmapause region as a boundary layer has been the longstanding tendency of textbooks on space physics to limit introductory material on the plasmapause phenomenon to zeroth order descriptions in terms of ideal MHD theory, thus implying that the plasmasphere is relatively well understood. A textbook may introduce the concept of shielding of the inner magnetosphere from perturbing convection electric fields, but attention is not usually paid to the variety of physical processes reported to occur in the PBL, such as heating, instabilities, and fast longitudinal flows, processes which must play roles in plasmasphere dynamics in concert with the flow regimes associated with the major dynamo sources of electric fields. We believe that through the use of the PBL concept in future textbook discussions of the plasmasphere and in scientific communications, much progress can be made on longstanding questions about the physics involved in the formation of the plasmapause and in the cycles of erosion and recovery of the plasmasphere.

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Stimulation of plasma waves in the magnetosphere using satellite JIKIKEN (EXOS-B). Part II. Plasma Density across the plasmapause.

Cited by 22 publications

References 37 publications

Relationship Between the Locations of the Midlatitude Trough and Plasmapause Using GNSS‐TEC and Arase Satellite Observation Data

Relationship Between the Locations of the Midlatitude Trough and Plasmapause Using GNSS‐TEC and Arase Satellite Observation Data

Investigation of Small‐Scale Electron Density Irregularities Observed by the Arase and Van Allen Probes Satellites Inside and Outside the Plasmasphere

The Plasmasphere Boundary Layer

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