Interaction of substorm injections with the subauroral geospace: 1. Multispacecraft observations of SAID

Mishin, E. V.

doi:10.1002/jgra.50548

Cited by 83 publications

(230 citation statements)

References 105 publications

(153 reference statements)

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“…Previous works have implied that SAIDS and SAPS are generated in the same way (e.g., Mishin, 2013). However, SAIDs are more closely associated with substorms (Anderson et al, 1993).…”

Section: Model Resultsmentioning

confidence: 96%

“…However, recent works (e.g., Mishin, 2013) have reported that R2 FACs are concentrated near the poleward boundary of SAPS and do not enclose the channel, which is inconsistent with the current-generator theory. Alternatively they have proposed another concept that a SAPS is a turbulent plasmaspheric boundary layer via a short circuiting of the plasmoid within the ambient plasma in the plasmasphere (e.g., Mishin, 2013).…”

Section: Introductionmentioning

confidence: 77%

“…The subauroral polarization stream (SAPS) is one of the interesting and important features of the magnetosphereionosphere-thermosphere coupling processes in the subauroral region, representing the rapid westward plasma flow predominantly in the dusk and premidnight sector (16-24 magnetic local time, MLT) (e.g., Galperin et al, 1974;Spiro et al, 1979;Anderson et al, 1991Anderson et al, , 1993Anderson et al, , 2001Yeh et al, 1991;Fejer and Scherliess, 1998;Scherliess and Fejer, 1998;Rowland and Wygant, 1998;Wygant et al, 1998;Ridley et al, 2002;Foster and Vo, 2002;Garner et al, 2004;Figueiredo et al, 2004;Liemohn et al, 2005;Jensen and Fejer, 2007;Zheng et al, 2008;Erickson et al, 2010Erickson et al, , 2011Clausen et al, 2012;Mishin, 2013). Two types of plasma flows have been classified in the literature: (1) polarization jets (PJ) (Galperin et al, 1974) or subauroral ion drifts (SAIDS) (Spiro et al, 1979), featured as more intense (∼ 1000 m s −1 ) and latitudinally confined (≤ 1 • latitude) plasma flow; and (2) a wider latitudinal extent and longer duration of plasma flow (Yeh et al, 1991).…”

Section: Introductionmentioning

confidence: 99%

“…SAPS can deepen the F region trough density (e.g., Smiddy et al, 1977;Maynard, 1978;Spiro et al, 1978;Anderson et al, 1991Anderson et al, , 2001Foster et al, 2007), enhance the electron temperature (e.g., Wang and Lühr, 2013;Mishin, 2013), contribute to the ion upflow (e.g., Yeh and Foster, 1990;Anderson et al, 1991;Moffett et al, 1992;Erickson et al, 2010;Wang and Lühr, 2013), and induce strong scintillations of UHF (ultra-high frequency) and L-band signals (e.g., Basu et al, 2008). Recent studies have disclosed that SAPS can cause westward wind jets and air density anomalies, which peak at the same location (e.g., Wang et al, 2012a, b;Wang et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

“…Alternatively they have proposed another concept that a SAPS is a turbulent plasmaspheric boundary layer via a short circuiting of the plasmoid within the ambient plasma in the plasmasphere (e.g., Mishin, 2013). Enhanced plasma waves within the SAPS channel lead to anomalous circuit resistivity and magnetic diffusion, as in the plasmoid-magnetic barrier problem.…”

Section: Introductionmentioning

confidence: 99%

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The spatial distribution of region 2 field-aligned currents relative to subauroral polarization stream

et al. 2014

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Abstract. To test the current-generation model of subauroral polarization stream (SAPS), we have investigated the relative positions of field-aligned currents (FACs) with respect to SAPS in a statistical way by using CHAMP (CHAllenging Minisatellite Payload) and DMSP (Defense Meteorological Satellite Program) satellite observations as well as model simulations. Comparative studies have been performed for consecutive CHAMP observations in different magnetic local time (MLT) sectors with respect to SAPS. The latitude of the peak westward zonal wind deduced from CHAMP measurements has been used to represent the location of the SAPS peak. Both the density and the sheet current strength of R2 (region 2) FACs are enhanced when SAPS occur. Subsequently R2 FACs decay in intensity and correspondingly the centers retreat poleward. The latitudes of the center of the R2 FAC, small-and medium-scale FACs, and SAPS shift equatorward with increasing MLT. The SAPS peaks are located between R2 and R1 (region 1) FAC peaks in all MLT bins under study. The SAPS peaks are closer to R2 centers in the later MLT sectors. The peaks of small-and mediumscale FACs are located poleward of SAPS, mainly in the upward R1 FACs region. The upward R1 FACs are partly closed by the downward R1 FACs in the dawn-morning sector. Based on model simulation, when R2 shifts equatorward to the subauroral region, the plasma flow also shifts equatorward with its peak located poleward of that of R2 FACs. Both the model and observations provide evidence that SAPS behave as caused by a magnetospheric current source.

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“…Previous works have implied that SAIDS and SAPS are generated in the same way (e.g., Mishin, 2013). However, SAIDs are more closely associated with substorms (Anderson et al, 1993).…”

Section: Model Resultsmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 77%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The spatial distribution of region 2 field-aligned currents relative to subauroral polarization stream

et al. 2014

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Fine structure of subauroral electric field and electron content

Makarevich

Bristow

2014

JGR Space Physics

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Citation:Makarevich, R. A., and W. A. Bristow (2014) Abstract Small-scale structure of the plasma convection and electron content within the subauroral polarization stream (SAPS) is investigated. We present ionospheric observations during the main phase of the geomagnetic storm on 17 March 2013, during which a sequence of intense, highly localized, and fast-moving electric field (EF) structures within SAPS was observed by the Super Dual Auroral Radar Network Christmas Valley West (CVW) radar. The CVW EF measurements at 60 s resolution are analyzed in context of coincident GPS measurements of the total electron content (TEC) at 30 s resolution. The strong and narrow feature of the subauroral ion drift (SAID) was observed poleward of the TEC trough, with a TEC enhancement (peak) seen in the SAPS (SAID) region. The SAPS wave activity commenced ∼2 h (15 min) after first appearance of SAPS (SAID). The SAPS structures appeared near the poleward edge of the trough, propagated westward, and merged with SAID near TEC peak. The propagation velocity was comparable with convection velocity within each EF structure. The SAPS TEC exhibited a general decrease toward the end of the period. On a smaller time scale, TEC exhibited a small but appreciable decrease within EF structures. The wavelet spectra of EF and TEC showed similar variations, with wave period of ∼5 min period near onset and increasing to 8-10 min toward the end of the period with significant wave activity. A scenario is discussed, in which the SAPS wave activity may modify the ionospheric conductance and TEC at small scales, with large-scale magnetosphere-ionosphere feedback acting to continuously deplete TEC where/when such activity does not occur.

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Nonlinear evolution of the temperature gradient instability in the midlatitude ionosphere

Eltrass

Scales

2014

JGR Space Physics

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The midlatitude Super Dual Auroral Radar Network radars frequently observe quiet time decameter‐scale irregularities in the nightside subauroral ionosphere. Since opposed temperature and density gradients are a persistent feature in the vicinity of the ionospheric projection of the plasmapause, the temperature gradient instability (TGI) is proposed to explain the observed irregularities. In this paper, modeling of the TGI is extended into the kinetic regime appropriate for HF radar frequencies and analyzed as the cause of these irregularities. The nonlinear evolution of the TGI is investigated utilizing gyrokinetic particle‐in‐cell simulation techniques with Monte Carlo collisions for the first time. The purpose of this investigation is to identify the mechanism responsible for the nonlinear saturation as well as the associated anomalous transport. It is found that the saturation amplitude level and the associated diffusion are greatly enhanced as a result of electron collisions. The simulation results indicate that the nonlinear E×Bconvection (trapping) of the electrons is the dominant TGI saturation mechanism. The spatial power spectra of the electrostatic potential and density fluctuations associated with the TGI are also computed, and the results show wave cascading of TGI from kilometer scales into the decameter‐scale regime of the radar observations. This implies that the E region may be responsible for shorting out the F region TGI electric fields before and around sunset. This also suggests that the observed midlatitude decameter‐scale ionospheric irregularities may be produced directly by the TGI or by turbulent cascade from primary longer‐wavelength irregularity structures produced from this instability.

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Interaction of substorm injections with the subauroral geospace: 1. Multispacecraft observations of SAID

Cited by 83 publications

References 105 publications

The spatial distribution of region 2 field-aligned currents relative to subauroral polarization stream

The spatial distribution of region 2 field-aligned currents relative to subauroral polarization stream

Fine structure of subauroral electric field and electron content

Nonlinear evolution of the temperature gradient instability in the midlatitude ionosphere

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