Equatorially confined warm trapped ions at around 100 eV near the plasmapause

Yamauchi, M.; Dandouras, I.; Rème, H.; Mazouz, F. El-Lemdani

doi:10.1029/2012gl052366

Cited by 6 publications

(15 citation statements)

References 17 publications

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“…However, they only reported five of such events, all of them occurring at energies < 1 keV and within the first 13 months of CIS observations. While there have been numerous observations and studies of heavy ions in the magnetosphere, most of them have covered higher energies (typical energies of the ring current, >50 keV) [Keika et al, 2006;Gerrard et al, 2014aGerrard et al, , 2014bKronberg et al, 2015], or lower energies (sub-keV energies) [Yamauchi et al, 2012], or have considered only O + [Sharp et al, 1976;Kistler et al, 1999;Greenspan and Hamilton, 2002;Korth et al, 2002;Mitchell et al, 2003;Keika et al, 2006Keika et al, , 2013Ebihara et al, 2009;Maggiolo and Kistler, 2014;Kronberg et al, 2015], or only He + [Yamauchi et al, 2014], or have focused solely on storm times [Fu et al, 2001;Greenspan and Hamilton, 2002;Ebihara et al, 2009;Forster et al, 2013], or have covered larger geocentric distances (beyond geostationary distance) [Kistler et al, 1990[Kistler et al, , 2006Nosé et al, 2009;Mouikis et al, 2010;Maggiolo and Kistler, 2014]. Overall, there have been more studies on O + than on He + in the inner magnetosphere, probably because O + ions are normally more abundant and contribute more significantly to the plasma sheet and ring current mass density.…”

Section: Introductionmentioning

confidence: 99%

Heavy‐ion dominance near Cluster perigees

et al. 2015

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Time periods in which heavy ions dominate over H+ in the energy range of 1–40 keV were observed by the Cluster Ion Spectrometry (CIS)/COmposition DIstribution Function (CODIF) instrument onboard Cluster Spacecraft 4 at L values less than 4. The characteristic feature is a narrow flux peak at around 10 keV that extends into low L values, with He+ and/or O+ dominating. In the present work we perform a statistical study of these events and examine their temporal occurrence and spatial distribution. The observed features, both the narrow energy range and the heavy‐ion dominance, can be interpreted using a model of ion drift from the plasma sheet, subject to charge exchange losses. The narrow energy range corresponds to the only energy range that has direct drift access from the plasma sheet during quiet times. The drift time to these locations from the plasma sheet is > 30 h, so that charge exchange has a significant impact on the population. We show that a simple drift/loss model can explain the dependence on L shell and MLT of these heavy‐ion‐dominant time periods.

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Section: Introductionmentioning

confidence: 99%

Heavy‐ion dominance near Cluster perigees

et al. 2015

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“…Yamauchi et al . [] reported that about one third of the equatorially trapped warm ions [e.g., Olsen et al ., ; Blanc et al ., ] include the He + signature at higher energies than H + . However, the equatorially trapped warm ions are found at all MLT and all geomagnetic conditions.…”

Section: Summary and Discussionmentioning

confidence: 99%

“…Although this He + event lasted nearly an hour, which is enough to cause some dispersion at this energy according to both past observations and simulations [ Yamauchi et al ., , ], the energization location is expected to be close to the spacecraft location because there is no energy‐time (energy‐latitude) dispersion in Figures b, h, and n. Instead, the highest He + energy flux density was found at a rather constant energy (around 70 eV) while the intensity decreased during 08:01–08:08 UT in Cluster‐1 and 08:23–08:32 UT in Cluster‐4.…”

Section: Cluster Observationsmentioning

confidence: 94%

Cluster observations of hot He⁺ events in the inner magnetosphere

et al. 2014

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In the inner magnetosphere inside 65°invariant latitude, Cluster Ion Spectrometry detected hot He + events of about a few tens to several hundred eV without the same types of hot H + signature at the same energy. During the 2001-2006 period when the Cluster orbit was almost constant and approximately north-south symmetric at constant local time near the perigee, we found nearly 20 examples in Cluster spacecraft 4. These hot He + events are morphologically classified into two burst types and two dispersed types: (1) Short intensification of He + (1a) without corresponding H + or O + signatures, or (1b) with H + signature at different pitch angles. (2) Energy-latitude dispersed He + stripes that continues for tens of minutes at hundreds to a few thousand eV range (2a) at different drift shell from energy-latitude dispersed H + stripes, or (2b) with very weak H + signature if the energy is constant. While type-1a is observed during or right after substorm activities, type-2b is found after long quiet periods, i.e., after long drift. The relationship with the geomagnetic activity indicates that the plasmasphere can be energized in a mass-dependent way in the evening sector during substorms to form the bursty types (type-1), while the selective He + energization can also take place during quiet periods near the noon. On the other hand, the source of the two dispersed types (type-2) must be remote from the observation point, and the location and the geomagnetic conditions at the time of the He + filtering is an open question.

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“…Fig. 10 shows one such example observed by Cluster (Yamauchi et al, 2012). Just limiting to the geocentric distance that Cluster traversed (4.0-4.5 R E at equator) and to ions more than 30 eV (strong heating), these ions are found nearly half the noon-dusk traversals during solar maximum, while probability is slightly lower in the night-dawn traversals because these ions are normally found at shorter geocentric distance there.…”

Section: Dynamics Of Cold Plasmaspheric Ionsmentioning

confidence: 98%

“…Cluster hot ion energy-time spectrograms of differential energy fluxes (keV cm −2 s −1 str −1 keV −1 ) during perigee traversal on 3 January 2002(Yamauchi et al, 2012). The most field-aligned sector and the most perpendicular sectors to the geomagnetic field are plotted.…”

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confidence: 99%

Terrestrial ion circulation in space

Yamauchi¹

2019

Preprint

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Abstract. Observations of the terrestrial ion transport and budget in the magnetosphere are reviewed, with stress on low energy ions in the high-altitude polar region and inner magnetosphere, for which Cluster significantly improved the knowledge. Outflowing ions from the ionosphere are classified into three types in terms of energy: (1) as cold ions refilling the plasmasphere faster than Jeans escape, (2) as cold supersonic ions such as the polar wind, and (3) as suprathermal ions energized by wave-particle interaction or parallel potential acceleration. Majority of the suprathermal ions are further energized at higher altitudes becoming hot with much higher velocity than the escape velocity even for heavy ions. This makes heavy ions in this category more abundant than cold refilling or cold supersonic flow. The immediate destination of these terrestrial ions varies from the plasmasphere, the inner magnetosphere including those entering to the ionosphere in the other, the magnetotail, and the solar wind (magnetosheath and cusp/plasma mantle). Due to time variable return from the magnetotail, ions with different routes and energy meet in the inner magnetosphere, making it a zoo of different types of ions in both energy and energy distribution. This zoo is not yet completely entangled, and includes many unanswered phenomena such as mass-dependent energization although the mass-independent drift theory is well justified. Nearly half of heavy ions in this zoo also finally escape to space, mainly due to magnetopause shadowing (overshooting of ion drift beyond the magnetopause) and charge exchange near the mirror altitude where the exospheric neutral density is the highest. The amount of heavy ions mixing with the solar wind is already the same or larger than that into the magnetotail, and is large enough to directly extract the solar wind kinetic energy in the cusp/plasma mantle through the mass-loading effect and drive the cusp current system. Considering the past solar and solar wind conditions, ion escape might have even influenced the evolution of the terrestrial biosphere.

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Equatorially confined warm trapped ions at around 100 eV near the plasmapause

Cited by 6 publications

References 17 publications

Heavy‐ion dominance near Cluster perigees

Heavy‐ion dominance near Cluster perigees

Cluster observations of hot He⁺ events in the inner magnetosphere

Terrestrial ion circulation in space

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Equatorially confined warm trapped ions at around 100 eV near the plasmapause

Cited by 6 publications

References 17 publications

Heavy‐ion dominance near Cluster perigees

Heavy‐ion dominance near Cluster perigees

Cluster observations of hot He+ events in the inner magnetosphere

Terrestrial ion circulation in space

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Product

Resources

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Cluster observations of hot He⁺ events in the inner magnetosphere