Previously hidden low-energy ions: a better map of near-Earth space and the terrestrial mass balance

André, Mats

doi:10.1088/0031-8949/90/12/128005

Cited by 11 publications

(13 citation statements)

References 121 publications

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“…The same can be said for Mars-like and Venus-like planets. With the current outflow rate of 1 kg s −1 , less than 1% of Earth's atmosphere is removed in a gigayear (André 2015). Even the maximum escape rates in Fig.…”

Section: Conclusion and Discussionmentioning

confidence: 95%

Why an intrinsic magnetic field does not protect a planet against atmospheric escape

Gunell

Maggiolo

Nilsson

et al. 2018

A&A

108

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The presence or absence of a magnetic field determines the nature of how a planet interacts with the solar wind and what paths are available for atmospheric escape. Magnetospheres form both around magnetised planets, such as Earth, and unmagnetised planets, like Mars and Venus, but it has been suggested that magnetised planets are better protected against atmospheric loss. However, the observed mass escape rates from these three planets are similar (in the approximate (0.5−2) kg s −1 range), putting this latter hypothesis into question. Modelling the effects of a planetary magnetic field on the major atmospheric escape processes, we show that the escape rate can be higher for magnetised planets over a wide range of magnetisations due to escape of ions through the polar caps and cusps. Therefore, contrary to what has previously been believed, magnetisation is not a sufficient condition for protecting a planet from atmospheric loss. Estimates of the atmospheric escape rates from exoplanets must therefore address all escape processes and their dependence on the planet's magnetisation.

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Section: Conclusion and Discussionmentioning

confidence: 95%

Why an intrinsic magnetic field does not protect a planet against atmospheric escape

Gunell

Maggiolo

Nilsson

et al. 2018

A&A

108

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“…The destination of the cold supersonic outflow is not yet clear except the tail plasma sheet because the measurement is possible only in the low-desity lobe region (Engwall et al, 2006;André, 2015). Since the observation is not easy, we have no knowledge on the other possible destinations.…”

Section: Known Destination For Cold Supersonic Outflowmentioning

confidence: 99%

“…A significant flux of ions enters the near-Earth tail plasma sheet (−10 R E < X < −20 R E ) as the primary destination for both the cold supersonic outflow (Engwall et al, 2009;André, 2015) and the suprathermal/hot outflow (Sauvaud et al, 2004;Maggiolo and Kistler, 2014;Slapak et al, 2017b). This make the plasma sheet a mixture of time-variable terrestrial ions into relatively stable solar wind ions, including the O + /H + ratio for terrestrial ions and the He ++ /H + ratio for the solar wind (Lennartsson, 1997(Lennartsson, , 2001Nosé et al, 2009).…”

Section: Secondary Destinations From the Near-earth Tailmentioning

confidence: 99%

“…Likewise, outflow of ionospheric heavy ions has also been observed (e.g., Moore et al, 1999, André, 2015. There are three types of outflow, which is mainly classified by detection method: (1) cold filling to the plasmasphere (Park, 1974, Welling et al, 2015, (2) cold supersonic outflow to the inner magnetosphere and magnetotail such as polar wind (Sue et al, 1998;Engwall et al, 2006;, and (3) ions with suprathermal energy above the ionosphere (e.g., Eliasson et al, 1994) or with higher energy at higher altitude (e.g., Möbius et al, 1998).…”

Section: Introductionmentioning

confidence: 99%

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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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“…The ultimate source of main phase ring current is the inward convection of plasma from the nightside plasma sheet region (Keika et al 2013). André (2015) developed a new technique to detect low-energy (eV) ionospheric ions by detecting the wake behind a charged spacecraft in a supersonic ion flow. Ionospheric ions are a major source of the magnetospheric plasma during a geomagnetic storm and quiet conditions (Chappell et al 1987).…”

Section: Introductionmentioning

confidence: 99%

Characteristics of storm time ion composition in the near-Earth plasma sheet using Geotail and RBSP measurements

Pandya

Veenadhari

Nosé

et al. 2018

Earth Planets Space

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Solar wind particles and ionospheric O + ions influence the near-Earth plasma sheet and inner magnetospheric composition. We studied the behavior of H + , O + and He + ions (9-210 keV) for intense and moderate geomagnetic storms of solar cycle 23 and 24. An average energy density < ε > of ions over a given interval and flux enhancement is estimated using observations from satellites at different L values, namely STICS sensor on-board Geotail spacecraft and HOPE spectrometer on-board Radiation Belt Storm Probes. It provides a comprehensive understanding of the energy density variation of H + , O + and He + ions with the strength of IMF Bz, Psw, intensity of storms and L value. Statistically, we observed that (1) In the plasma sheet region, during main phase of the intense geomagnetic storm, < ε O+/H+ > and < ε He+/H+ > enhances, (2) < ε O+/H+ > is well correlated with Psw (CC = 0.86) and IMF Bz (CC = 0.85), (3) < ε O+/H+ > shows higher correlation (CC = 0.73) with Kp than < ε He+/H+ > (CC = 0.65), indicating a fairly good dependence on the strength of geomagnetic activity, (4) < ε O+/H+ > and < ε He+/H+ > dependence on L value indicates that O + /H + and He + /H + is more pronounced near L = 3. It is a cumulative extension of the previous studies on ion composition change which is in accordance with the existing picture of the plasma sheet and inner magnetosphere. which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.

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Previously hidden low-energy ions: a better map of near-Earth space and the terrestrial mass balance

Cited by 11 publications

References 121 publications

Why an intrinsic magnetic field does not protect a planet against atmospheric escape

Why an intrinsic magnetic field does not protect a planet against atmospheric escape

Terrestrial ion circulation in space

Characteristics of storm time ion composition in the near-Earth plasma sheet using Geotail and RBSP measurements

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