Ion Acceleration and Outflow from Mars and Venus: An Overview

Lundin, R.

doi:10.1007/s11214-011-9811-y

Cited by 80 publications

(78 citation statements)

References 88 publications

(131 reference statements)

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“…An ion can be lost everywhere outside the magnetosphere/ionosphere of a planet. This mechanism has been observed to be effective for presentday Mars and Venus (see for example Lundin 2011). Their atmospheres also do not extend beyond the L 1 point.…”

Section: Ion Production and Pick-up Escapementioning

confidence: 88%

Stellar wind interaction and pick-up ion escape of the Kepler-11 “super-Earths”

Kislyakova

Johnstone

Odert

et al. 2014

A&A

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Aims. We study the interactions between stellar winds and the extended hydrogen-dominated upper atmospheres of planets. We estimate the resulting escape of planetary pick-up ions from the five "super-Earths" in the compact Kepler-11 system and compare the escape rates with the efficiency of the thermal escape of neutral hydrogen atoms. Methods. Assuming the stellar wind of Kepler-11 is similar to the solar wind, we use a polytropic 1D hydrodynamic wind model to estimate the wind properties at the planetary orbits. We apply a direct simulation Monte Carlo model to model the hydrogen coronae and the stellar wind plasma interaction around Kepler-11b-f within a realistic expected heating efficiency range of 15-40%. The same model is used to estimate the ion pick-up escape from the XUV heated and hydrodynamically extended upper atmospheres of Kepler-11b-f. From the interaction model, we study the influence of possible magnetic moments, calculate the charge exchange and photoionization production rates of planetary ions, and estimate the loss rates of pick-up H + ions for all five planets. We compare the results between the five "super-Earths" and the thermal escape rates of the neutral planetary hydrogen atoms. Results. Our results show that a huge neutral hydrogen corona is formed around the planet for all Kepler-11b-f exoplanets. The nonsymmetric form of the corona changes from planet to planet and is defined mostly by radiation pressure and gravitational effects. Nonthermal escape rates of pick-up ionized hydrogen atoms for Kepler-11 "super-Earths" vary between ∼6.4×10 30 s −1 and ∼4.1×10 31 s −1 , depending on the planet's orbital location and assumed heating efficiency. These values correspond to non-thermal mass loss rates of ∼1.07 × 10 7 g s −1 and ∼6.8 × 10 7 g s −1 respectively, which is a few percent of the thermal escape rates.

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Section: Ion Production and Pick-up Escapementioning

confidence: 88%

Stellar wind interaction and pick-up ion escape of the Kepler-11 “super-Earths”

Kislyakova

Johnstone

Odert

et al. 2014

A&A

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“…At Mars, observations of magnetic reconnection (Dubinin et al, 2008;Eastwood et al, 2008;Harada et al, 2015aHarada et al, , 2017, flux rope formation (DiBraccio et al, 2015;Eastwood et al, 2012;Hara et al, 2017), current sheet flapping , Marsward and tailward ion flows (Harada et al, 2015b), magnetic lobe dependence on IMF orientation Romanelli et al, 2015) and ionosphere magnetization , and bulk plasma escape (e.g., Brain et al, 2010;Halekas et al, 2016) have been reported in the magnetotail. Dong et al, , 2017Dubinin et al, 1993Dubinin et al, , 2011Lundin, 2011). Dong et al, , 2017Dubinin et al, 1993Dubinin et al, , 2011Lundin, 2011).…”

Section: 1029/2018gl077251mentioning

confidence: 99%

The Twisted Configuration of the Martian Magnetotail: MAVEN Observations

DiBraccio

Luhmann

Curry

et al. 2018

Geophysical Research Letters

110

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Measurements provided by the Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft are analyzed to investigate the Martian magnetotail configuration as a function of interplanetary magnetic field (IMF) BY. We find that the magnetotail lobes exhibit a ~45° twist, either clockwise or counterclockwise from the ecliptic plane, up to a few Mars radii downstream. Moreover, the associated cross‐tail current sheet is rotated away from the expected location for a Venus‐like induced magnetotail based on nominal IMF draping. Data‐model comparisons using magnetohydrodynamic simulations are in good agreement with the observed tail twist. Model field line tracings indicate that a majority of the twisted tail lobes are composed of open field lines, surrounded by draped IMF. We infer that dayside magnetic reconnection between the crustal fields and draped IMF creates these open fields and may be responsible for the twisted tail configuration, similar to what is observed at Earth.

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“…A number of processes govern the loss of the Martian and Venusian atmospheres (e.g., Nagy et al 2004;Lammer et al 2006;Lundin 2011). Some invoke bombardment and hydrodynamic outflow.…”

Section: Mars and Venusmentioning

confidence: 99%

Imaging Plasma Density Structures in the Soft X-Rays Generated by Solar Wind Charge Exchange with Neutrals

et al. 2018

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Both heliophysics and planetary physics seek to understand the complex nature of the solar wind's interaction with solar system obstacles like Earth's magnetosphere, the ionospheres of Venus and Mars, and comets. Studies with this objective are frequently conducted with the help of single or multipoint in situ electromagnetic field and particle observations, guided by the predictions of both local and global numerical simulations, and placed in con- text by observations from far and extreme ultraviolet (FUV, EUV), hard X-ray, and energetic neutral atom imagers (ENA). Each proposed interaction mechanism (e.g., steady or transient magnetic reconnection, local or global magnetic reconnection, ion pick-up, or the KelvinHelmholtz instability) generates diagnostic plasma density structures. The significance of each mechanism to the overall interaction (as measured in terms of atmospheric/ionospheric loss at comets, Venus, and Mars or global magnetospheric/ionospheric convection at Earth) remains to be determined but can be evaluated on the basis of how often the density signatures that it generates are observed as a function of solar wind conditions. This paper reviews efforts to image the diagnostic plasma density structures in the soft (low energy, 0.1-2.0 keV) X-rays produced when high charge state solar wind ions exchange electrons with the exospheric neutrals surrounding solar system obstacles. The introduction notes that theory, local, and global simulations predict the characteristics of plasma boundaries such the bow shock and magnetopause (including location, density gradient, and motion) and regions such as the magnetosheath (including density and width) as a function of location, solar wind conditions, and the particular mechanism operating. In situ measurements confirm the existence of time-and spatial-dependent plasma density structures like the bow shock, magnetosheath, and magnetopause/ionopause at Venus, Mars, comets, and the Earth. However, in situ measurements rarely suffice to determine the global extent of these density structures or their global variation as a function of solar wind conditions, except in the form of empirical studies based on observations from many different times and solar wind conditions. Remote sensing observations provide global information about auroral ovals (FUV and hard X-ray), the terrestrial plasmasphere (EUV), and the terrestrial ring current (ENA). ENA instruments with low energy thresholds (∼ 1 keV) have recently been used to obtain important information concerning the magnetosheaths of Venus, Mars, and the Earth. Recent technological developments make these magnetosheaths valuable potential targets for high-cadence wide-field-of-view soft X-ray imagers.Section 2 describes proposed dayside interaction mechanisms, including reconnection, the Kelvin-Helmholtz instability, and other processes in greater detail with an emphasis on the plasma density structures that they generate. It focuses upon the questions that remain as yet unanswered, such as the significanc...

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Ion Acceleration and Outflow from Mars and Venus: An Overview

Cited by 80 publications

References 88 publications

Stellar wind interaction and pick-up ion escape of the Kepler-11 “super-Earths”

Stellar wind interaction and pick-up ion escape of the Kepler-11 “super-Earths”

The Twisted Configuration of the Martian Magnetotail: MAVEN Observations

Imaging Plasma Density Structures in the Soft X-Rays Generated by Solar Wind Charge Exchange with Neutrals

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