IMF dependence of energetic oxygen and hydrogen ion distributions in the near‐Earth magnetosphere

Luo, Hao; Kronberg, Elena A.; Nykyri, K.; Trattner, K. J.; Daly, P. W.; Chen, G. X.; Du, Aimin; Ge, Yasong

doi:10.1002/2016ja023471

Cited by 17 publications

(27 citation statements)

References 52 publications

(61 reference statements)

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“…There is a 1 order of magnitude difference between the SH and NH, which could be explained by the different relative location of the spatial boxes and the geomagnetic activity. A similar trend has been observed by Luo et al (2017), who studied the energetic ion distributions in the dayside magnetosphere and the plasma sheet. The authors found that there is a strong correlation between the dawn-dusk asymmetry and the IMF direction, with a higher asymmetry in the Southern Hemisphere.…”

Section: Most Extreme Casesupporting

confidence: 84%

Relative outflow enhancements during major geomagnetic storms – Cluster observations

et al. 2017

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Abstract. The rate of ion outflow from the polar ionosphere is known to vary by orders of magnitude, depending on the geomagnetic activity. However, the upper limit of the outflow rate during the largest geomagnetic storms is not well constrained due to poor spatial coverage during storm events. In this paper, we analyse six major geomagnetic storms between 2001 and 2004 using Cluster data. The six major storms fulfil the criteria of Dst < −100 nT or Kp > 7+. Since the shape of the magnetospheric regions (plasma mantle, lobe and inner magnetosphere) are distorted during large magnetic storms, we use both plasma beta (β) and ion characteristics to define a spatial box where the upward O + flux scaled to an ionospheric reference altitude for the extreme event is observed. The relative enhancement of the scaled outflow in the spatial boxes as compared to the data from the full year when the storm occurred is estimated. Only O + data were used because H + may have a solar wind origin. The storm time data for most cases showed up as a clearly distinguishable separate peak in the distribution toward the largest fluxes observed. The relative enhancement in the outflow region during storm time is 1 to 2 orders of magnitude higher compared to less disturbed time. The largest relative scaled outflow enhancement is 83 (7 November 2004) and the highest scaled O + outflow observed is 2 × 10 14 m −2 s −1 (29 October 2003).

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Section: Most Extreme Casesupporting

confidence: 84%

Relative outflow enhancements during major geomagnetic storms – Cluster observations

et al. 2017

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“…It is observationally known that~10-100 keV ions are the main components of the storm time ring current (e.g., Daglis et al, 1999;Kronberg et al, 2017) and that they are supplied into the ring current by convective transport (e.g., Gkioulidou et al, 2016). Luo et al (2017) reported that energetic (≳274 keV) oxygen ions can be transported to the dayside outer magnetosphere and plasma sheet via reconnection at the magnetopause. Lanzerotti and Gerrard (2016) and Gkioulidou et al (2016) reported that >100 keV protons are transported into the ring current by diffusive transport.…”

Section: Introductionmentioning

confidence: 99%

“…Lanzerotti and Gerrard (2016) and Gkioulidou et al (2016) reported that >100 keV protons are transported into the ring current by diffusive transport. Luo et al (2017) reported that energetic (≳274 keV) oxygen ions can be transported to the dayside outer magnetosphere and plasma sheet via reconnection at the magnetopause. However, there are few reports on radial transport of ≳100 keV oxygen ions into the ring current.…”

Section: Introductionmentioning

confidence: 99%

Radial Transport of Higher‐Energy Oxygen Ions Into the Deep Inner Magnetosphere Observed by Van Allen Probes

Mitani

Seki

Keika

et al. 2018

Geophysical Research Letters

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The transport mechanism of the ring current ions differs among ion energies. Lower‐energy (≲150 keV) ions are well known to be transported convectively. Higher‐energy (≳150 keV) protons are reported to be transported diffusively, while there are few reports about transport of higher‐energy oxygen ions. We report the radial transport of higher‐energy oxygen ions into the deep inner magnetosphere during the late main phase of the magnetic storm on 23–25 April 2013 observed by the Van Allen Probes spacecraft. An enhancement of 1–100 mHz magnetic fluctuations is simultaneously observed. Observations of 3 and 30 mHz geomagnetic pulsations indicate the azimuthal mode number is ≤10. The fluctuations can resonate with the drift and bounce motions of the oxygen ions. The results suggest that the combination of the drift and drift‐bounce resonances is responsible for the radial transport of higher‐energy oxygen ions.

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“…They found O + was the dominant contributor to the mass density (30 %) in the duskside magnetopause in comparison to 3 % in the dawnside and 4 % near noon. The dawn-dusk asymmetries of the energetic O + (>∼ 274 keV) distribution in three different regions (dayside magnetopause, near-Earth nightside plasma sheet, and tail plasma sheet) are also observed by Luo et al (2017). They found that the energetic O + distributions were mainly influenced by the dawn-dusk IMF directions and the enhancement of ion intensity strongly related to the location of the magnetopause reconnection.…”

Section: Introductionmentioning

confidence: 97%

“…The distribution of energetic oxygen ion density at the dayside magnetopause is asymmetric, and it has a close relationship with the interplanetary magnetic field (IMF) (e.g., Bouhram et al, 2005;Phan et al, 2004;Luo et al, 2017). Bouhram et al (2005) pointed out that the O + density in the duskside (on average 0.053 cm −3 ) magnetopause is higher than that in the dawnside (on average 0.014 cm −3 ).…”

Section: Introductionmentioning

confidence: 99%

Magnetospheric Multiscale observations of energetic oxygen ions at the duskside magnetopause during intense substorms

Zeng¹,

Duan²,

Wang³

et al. 2020

Ann. Geophys.

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Abstract. Energetic oxygen ions (1–40 keV) observed by the Magnetospheric Multiscale (MMS) satellites at the duskside magnetopause boundary layer during phase 1 are investigated. There are 57 duskside magnetopause crossing events identified during intense substorms (AE>500 nT). These 57 events of energetic O+ at the duskside magnetopause include 26 events during the expansion phase and 31 events during the recovery phase of intense substorms. It is found that the O+ density in the duskside magnetopause boundary layer during the recovery phase (0.081 cm−3) is larger than that during the expansion phase (0.069 cm−3). The 26 events of energetic O+ ions at the duskside magnetopause during intense substorm expansion phase are all under the southward interplanetary magnetic field (IMF). There are only seven events under northward IMF, and they all occurred during the intense substorm recovery phase. The density of energetic O+ at the duskside magnetopause ranges from 0.007 to 0.599 cm−3. The maximum density of O+ occurred during the intense substorm recovery phase and under southward IMF. When the IMF is southward, the O+ density shows an exponential increase with the IMF Bz absolute value. Meanwhile, the O+/H+ density ratio shows an exponential growth with the IMF By. These results agree with previous studies in the near-Earth magnetosphere during intense substorm. It is suggested that O+ abundance in the duskside magnetopause boundary layer has a close relation to O+ variations in the near-Earth magnetosphere during intense substorms.

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IMF dependence of energetic oxygen and hydrogen ion distributions in the near‐Earth magnetosphere

Cited by 17 publications

References 52 publications

Relative outflow enhancements during major geomagnetic storms – Cluster observations

Relative outflow enhancements during major geomagnetic storms – Cluster observations

Radial Transport of Higher‐Energy Oxygen Ions Into the Deep Inner Magnetosphere Observed by Van Allen Probes

Magnetospheric Multiscale observations of energetic oxygen ions at the duskside magnetopause during intense substorms

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