Asymmetric ionospheric outflow observed at the dayside magnetopause

Lee, S. H.; Zhang, H.; Zong, Qiugang; Wang, Y.; Otto, A.; Rème, H.; Glassmeier, K.

doi:10.1002/2014ja020943

Cited by 19 publications

(15 citation statements)

References 39 publications

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“…The first encounter (event 1) was previously discussed by ; Graham et al [2015] and Wang et al [2015], and the second encounter (event 2) was previously discussed by Lee et al [2015] and Toledo-Redondo et al [2015]. The first encounter (event 1) was previously discussed by ; Graham et al [2015] and Wang et al [2015], and the second encounter (event 2) was previously discussed by Lee et al [2015] and Toledo-Redondo et al [2015].…”

Section: Events Overviewmentioning

confidence: 99%

“…Two Cluster magnetopause encounters are presented. The first encounter (event 1) was previously discussed by ; Graham et al [2015] and Wang et al [2015], and the second encounter (event 2) was previously discussed by Lee et al [2015] and Toledo-Redondo et al [2015]. [Balogh et al, 2001].…”

Section: Events Overviewmentioning

confidence: 99%

“…During high geomagnetic activity, these cold ions can escape to the outer magnetosphere in the form of drainage plumes, with densities of 10-100 cm −3 [Borovsky and Denton, 2008;Moore et al, 2008;Darrouzet et al, 2008Darrouzet et al, , 2009. In addition, cold ions can escape directly from the ionosphere following the magnetic field lines in the auroral regions [André and Yau, 1997;Yau et al, 2007;Lee et al, 2015]. In addition, cold ions can escape directly from the ionosphere following the magnetic field lines in the auroral regions [André and Yau, 1997;Yau et al, 2007;Lee et al, 2015].…”

Section: Introductionmentioning

confidence: 99%

“…When geomagnetic activity is low, there can still exist a plasmaspheric wind that carries cold ions to the outer magnetosphere via corotation [Matsui et al, 1999;André and Lemaire, 2006;Tu et al, 2007;Dandouras, 2013]. In addition, cold ions can escape directly from the ionosphere following the magnetic field lines in the auroral regions [André and Yau, 1997;Yau et al, 2007;Lee et al, 2015]. Cold ions are common in the dayside magnetosphere, up to the magnetopause [Sauvaud et al, 2001;André and Cully, 2012;Lee and Angelopoulos, 2014] and in the magnetotail lobe region [Engwall et al, 2009;André et al, 2015].…”

Section: Introductionmentioning

confidence: 99%

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Cold ion heating at the dayside magnetopause during magnetic reconnection

Toledo‐Redondo

André

Vaivads

et al. 2016

Geophysical Research Letters

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Cold ions of ionospheric origin are known to be present in the magnetospheric side of the Earth's magnetopause. They can be very abundant, with densities up to 100 cm−3. These cold ions can mass load the magnetosphere, changing global parameters of magnetic reconnection, like the Alfvén speed or the reconnection rate. In addition they introduce a new length scale related to their gyroradius and kinetic effects which must be accounted for. We report in situ observations of cold ion heating in the separatrix owing to time and space fluctuations of the electric field. When this occurs, the cold ions are preheated before crossing the Hall electric field barrier. However, when this mechanism is not present cold ions can be observed well inside the reconnection exhaust. Our observations suggest that the perpendicular cold ion heating is stronger close to the X line owing to waves and electric field gradients linked to the reconnection process.

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Section: Events Overviewmentioning

confidence: 99%

Section: Events Overviewmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Cold ion heating at the dayside magnetopause during magnetic reconnection

Toledo‐Redondo

André

Vaivads

et al. 2016

Geophysical Research Letters

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“…Mechanisms for generation of the cold plasmas in the dayside magnetosphere have been proposed as the plasmaspheric drainage plume [Borovsky and Denton, 2008] and direct ionosphere outflow [Lee et al, 2015]. Han et al [2015] found that DDAs in stripy form, approximately aligned in north-south direction, are frequently observed near MLN and suggested that stripy DDAs should be mapping to wedge-like cold plasma structures extending from low to high L shells in the dayside magnetosphere.…”

Section: Dayside Diffuse Auroras and The Cold Plasmas Originated Frommentioning

confidence: 99%

Coordinated observations of two types of diffuse auroras near magnetic local noon by Magnetospheric Multiscale mission and ground all‐sky camera

Han

Nishimura

et al. 2017

Geophysical Research Letters

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Structured diffuse auroras are often observed near magnetic local noon (MLN), but their generation mechanisms are poorly understood. We have found that two types of structured diffuse auroras with obviously different dynamical properties often coexist near MLN. One type usually drifts from low to high latitude with higher speed and shows pulsation. The other type is always adjacent to the discrete aurora oval and drifts together with nearby discrete aurora with much lower speed. Using coordinated observations from MMS and ground all‐sky imagers, we found that the two types of diffuse auroras are well correlated with number density increase of O+ (from the ionosphere) and of He2+ (from magnetosheath) ions, respectively. These observations indicate that mangetosheath particles penetrated into the magnetosphere also can play an important role for producing the dayside diffuse aurora. In addition, for the first time, electron cyclotron harmonic waves are observed associated with dayside diffuse aurora.

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An extensive survey of dayside diffuse aurora based on optical observations at Yellow River Station

et al. 2015

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By using 7 years optical auroral observations obtained at Yellow River Station (magnetic latitude 76.24°N) at Ny-Alesund, Svalbard, we performed the first extensive survey for the dayside diffuse auroras (DDAs) and acquired observational results as follows.(1) The DDAs can be classified into two broad categories, i.e., unstructured and structured DDAs. The unstructured DDAs are mainly distributed in morning and afternoon, but the structured DDAs predominantly occurred around the magnetic local noon (MLN). (2) The unstructured DDAs observed in morning and afternoon present obviously different properties. The afternoon ones are much stable and seldom show pulsating property. (3) The DDAs are more easily observed under geomagnetically quiet times. (4) The structured DDAs mainly show patchy, stripy, and irregular forms and are often pulsating and drifting. The drifting directions are mostly westward (with speed ~5 km/s), but there are cases showing eastward or poleward drifting. ( 5) The stripy DDAs are exclusively observed near the MLN and, most importantly, their alignments are confirmed to be consistent with the direction of ionospheric convection near the MLN. (6) A new auroral form, called throat aurora, is found to be developed from the stripy DDAs. Based on the observational results and previous studies, we proposed our explanations to the DDAs. We suggest that the unstructured DDAs observed in the morning are extensions of the nightside diffuse aurora to the dayside, but that observed in the afternoon are predominantly caused by proton precipitations. The structured DDAs occurred near the MLN are caused by interactions of cold plasma structures, which are supposed to be originated from the ionospheric outflows or plasmaspheric drainage plumes, with hot electrons from the plasma sheet. We suppose that the cold plasma structures for producing the patchy DDAs are in lumpy and are more likely from the plasmaspheric drainage plumes. The cold plasma structure for producing the stripy DDAs should be in wedge like and is generated by conveying the cold plasmas from lower L-shell toward higher L-shell with magnetospheric convection, and that for producing the irregular DDAs is resulted from deforming the wedge-like structure by disturbance. The throat aurora is supposed to be projection of a newly opened flux of reconnection. In addition, we also found that structured DDAs correspond to structured electron precipitations in the ionosphere, which implies that the cold plasma structures in the magnetosphere are magnetically mapped to the ionosphere and act as a duct for producing the structured DDAs. We argue that we have presented some new observational results about DDA in this paper, which will be useful for fully understanding the DDAs.

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Asymmetric ionospheric outflow observed at the dayside magnetopause

Cited by 19 publications

References 39 publications

Cold ion heating at the dayside magnetopause during magnetic reconnection

Cold ion heating at the dayside magnetopause during magnetic reconnection

Coordinated observations of two types of diffuse auroras near magnetic local noon by Magnetospheric Multiscale mission and ground all‐sky camera

An extensive survey of dayside diffuse aurora based on optical observations at Yellow River Station

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