Ring current oxygen ions escaping into the magnetosheath

Zong, Q.; Wilken, B.; Fu, Shizuo; Fritz, T. A.; Korth, A.; Hasebe, Nobuyuki; Williams, D. J.; Pu, Z. Y.

doi:10.1029/2000ja000127

Cited by 58 publications

(66 citation statements)

References 35 publications

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“…Contrary to interpretations of some previous reported events [e.g., Zong et al, 2001], the oxygen ions that we measure, with their large gyroradii, do not appear to be participating in field-aligned escape from the magnetosphere at the same time than are other ions with substantially smaller gyroradii. Zong et al…”

Section: 1002/2016gl070189contrasting

confidence: 54%

The permeability of the magnetopause to a multispecies substorm injection of energetic particles

Westlake

Cohen

Mauk

et al. 2016

Geophysical Research Letters

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Leakage of ions from the magnetosphere into the magnetosheath remains an important topic in understanding the plasma physics of Earth's magnetopause and the interaction of the solar wind with the magnetosphere. Here using sophisticated instrumentation from two spacecraft (Radiation Belt Storm Probes Ion Composition Experiment on the Van Allen Probes and Energetic Ion Spectrometer on the Magnetospheric Multiscale) spaced uniquely near and outside the dayside magnetopause, we are able to determine the escape mechanisms for large gyroradii oxygen ions and much smaller gyroradii hydrogen and helium ions. The oxygen ions are entrained on the magnetosphere boundary, while the hydrogen and helium ions appear to escape along reconnected field lines. These results have important implications for not only Earth's magnetosphere but also other solar system magnetospheres.

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Section: 1002/2016gl070189contrasting

confidence: 54%

The permeability of the magnetopause to a multispecies substorm injection of energetic particles

Westlake

Cohen

Mauk

et al. 2016

Geophysical Research Letters

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“…with energy of tens to hundreds keV (typically 20-200 keV) are thought to be the main carrier of the ring current energy [Williams, 1981[Williams, , 1983[Williams, , 1985. It is believed that the H + ions are the dominant ion species in the ring current during quiet times, while the O + ions become a significant contributor during geomagnetic activities [e.g., Daglis et al, 1999;Zong et al, 2001]. It has been reported that the O + ions (1-315 keV) could contributed 30-50% of the total ring current energy density during storm time, compared to less than 3% during quiet times Krimigis et al, 1985;Hamilton et al, 1988].…”

Section: Introductionmentioning

confidence: 99%

The role of ULF waves interacting with oxygen ions at the outer ring current during storm times

Yang

Zong

et al. 2011

J. Geophys. Res.

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[1] The modulations of the outer ring current O + ion fluxes by ULF Pc5 waves are investigated by multisatellite observations during storm times. The O + ions have energies up to tens of keV. We concentrate on the process in terms of drift-bounce resonance of O + ions with ULF standing waves to understand whether the ring current O + ions could be accelerated/decelerated by ULF waves. Two case studies are performed, in which the Cluster satellites travel the outer ring current region in the morning sector with radial distances of about 5.5 R E . Distinct O + ion flux oscillations are observed associated with fundamental mode ULF standing waves. On 25 October 2002, both satellites SC1 and SC4 observe strong poloidal and toroidal standing waves at approximately the same region one by one with a time lag of 45 min. The O + ion flux oscillations at around 20 keV are dominantly coherent with the poloidal standing wave at 3.4 mHz with cross phases of near 90°with respect to the magnetic field waves. The O + phase space density spectra at 10 to 25 keV, measured by both satellites, deviate significantly from the typical power law distribution. We suggest that the O + ions at 10 to 25 keV are accelerated due to drift-bounce resonance with the poloidal standing wave. On 4 November 2002, satellite SC1 observes considerable poloidal and toroidal standing waves. The O + ion flux oscillation at around 7 keV is well correlated with both of the two wave modes at 3.7 mHz with cross phases of about 90°with respect to the magnetic field waves. The O + spectra at 4 to 8 keV deviates remarkably from the background power law distribution. When satellite SC4 closely encounters the same region 40 min later, the wave activities at 3.7 mHz are found to be rather weak and the O + spectra is close to the background power law distribution. We suggest that the spectra variation of SC1 results from the deceleration of O + ion at 4 to 8 keV via drift-bounce resonances during the strong wave activities. The observations made in this study reveal the effective role of ULF standing waves in accelerating/decelerating the ring current O + ions.Citation: Yang, B., Q.-G. Zong, S. Y. Fu, X. Li, A. Korth, H. S. Fu, C. Yue, and H. Reme (2011), The role of ULF waves interacting with oxygen ions at the outer ring current during storm times,

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“…Then we obtain λ∼3×10 21 s −1 . This value is much smaller than the oxygen ion loss rates across the magnetopause estimated by Seki et al (2001) and Zong et al (2001): ∼10 23 to 10 24 s −1 (the former and the latter assumed the open areas of ∼30 R E 2 and 5 R E 2 , respectively). However, our integration is limited to the high energies (>180 keV), hence the estimation is rather low.…”

Section: Outflow Rates and The Contribution To D St Recoverymentioning

confidence: 53%

“…Although the escape via magnetic reconnection at a low latitude during southward Interplanetary magnetic field (IMF) has been reported (Speiser et al, 1981;Daly et al, 1984;Zong et al, 2001), there is little discussion on the escape via magnetic reconnection during northward IMF periods. One exception is the study by Onsager et al (2001) who showed anisotropic phase space densities of ions (without mass discrimination) observed by the Polar spacecraft during northward IMF, and suggested that the ion escape was due to high-latitude reconnection with the closed magnetospheric field lines.…”

Section: Introductionmentioning

confidence: 99%

“…On the other hand, Zong et al (2001) examined a storm event by using Geotail data, and found that oxygen ions (>∼150 keV) escape through magnetic reconnection between the southward magnetosheath field and magnetospheric field lines near the equator. Although the escape via magnetic reconnection at a low latitude during southward Interplanetary magnetic field (IMF) has been reported (Speiser et al, 1981;Daly et al, 1984;Zong et al, 2001), there is little discussion on the escape via magnetic reconnection during northward IMF periods.…”

Section: Introductionmentioning

confidence: 99%

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Escape of high-energy oxygen ions through magnetopause reconnection under northward IMF

et al. 2008

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Abstract. During a storm recovery phase on 15 May 2005, the Geotail spacecraft repeatedly observed highenergy (>180 keV) oxygen ions in the dayside magnetosheath near the equatorial plane. We focused on the time period from 11:20 UT to 13:00 UT, when Geotail observed the oxygen ions and the interplanetary magnetic field (IMF) was constantly northward. The magnetic reconnection occurrence northward and duskward of Geotail is indicated by the Walén analysis and convective flows in the magnetopause boundary layer. Anisotropic pitch angle distributions of ions suggest that high-energy oxygen ions escaped from the northward of Geotail along the reconnected magnetic field lines. From the low-energy particle precipitation in the polar cap observed by DMSP, which is consistent with magnetic reconnection occurring between the magnetosheath field lines and the magnetospheric closed field lines, we conclude that these oxygen ions are of ring current origin. Our results thus suggest a new escape route of oxygen ions during northward IMF. In the present event, this escape mechanism is more dominant than the leakage via the finite Larmor radius effect across the dayside equatorial magnetopause.

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Ring current oxygen ions escaping into the magnetosheath

Cited by 58 publications

References 35 publications

The permeability of the magnetopause to a multispecies substorm injection of energetic particles

The permeability of the magnetopause to a multispecies substorm injection of energetic particles

The role of ULF waves interacting with oxygen ions at the outer ring current during storm times

Escape of high-energy oxygen ions through magnetopause reconnection under northward IMF

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