Oxygen Ion Energization at Mars: Comparison of MAVEN and Mars Express Observations to Global Hybrid Simulation

Järvinen, R.; Brain, David; Modolo, Ronan; Fedorov, A.; Holmström, Mats

doi:10.1002/2017ja024884

Cited by 29 publications

(38 citation statements)

References 47 publications

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“…The precipitating ions with energy higher than the solar wind (800 eV to 1 keV) are formed in the southern hemisphere MSE, and their final energy depends on their altitude of creation (by ionization). This energy‐altitude injection relation is consistent with Jarvinen et al (2018) and can be explained by the time spent by an ion in the high electric field regions (essentially the solar wind and the magnetosheath). In the northern hemisphere, it can also be seen that precipitating ions are mainly formed within or downstream of the pileup magnetic region.…”

Section: Lathys‐simulated Precipitation and Maven Precipitating Measusupporting

confidence: 91%

Influence of the Solar Wind Dynamic Pressure on the Ion Precipitation: MAVEN Observations and Simulation Results

et al. 2020

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We discuss the influence of the solar wind dynamic pressure on the ion precipitation using observations performed by MAVEN from 4 June 2014 to 20 July 2017. The increase of the dynamic pressure from 0.63 to 1.44 nPa is clearly associated with an increase of the same order of magnitude of the precipitating oxygen ion energy flux measured by MAVEN/STATIC from 9.9 to 20.6 × 10 6 eV • cm −2 • sr −1 • s −1 at low energy (from 30 to 650 eV). In the same way, from 650 to 25,000 eV, MAVEN/SWIA (all species) observed an increase from 22.4 to 42.8 × 10 7 eV • cm −2 • sr −1 • s −1 of the precipitating ion energy flux. Performing two simulations using the average solar wind conditions for both solar dynamic pressure regimes observed by MAVEN as input of the LatHyS model (LATMOS Hybrid Simulation), we reproduce some of the key characteristics of the observed oxygen ion precipitation. We characterize the oxygen ions simulated by LatHyS by their energy and time of impact, their time of injection in the simulation and initial position, and the mechanism by which these ions were created. The model suggests that the main cause of the increase of the heavy ion precipitation during an increase of the solar dynamic pressure is the increase of the ion production by charge exchange, proportional to the increase of the solar wind flux, which becomes the main contribution to the ion precipitation at high energy.

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Section: Lathys‐simulated Precipitation and Maven Precipitating Measusupporting

confidence: 91%

Influence of the Solar Wind Dynamic Pressure on the Ion Precipitation: MAVEN Observations and Simulation Results

et al. 2020

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“…The two hybrid simulations were run using two different codes: HELIOSARES (Modolo et al, ), and RHybrid (Jarvinen et al, ). As hybrid codes they both treat ions as macroparticles that evolve kinetically according to the Lorentz force, while the electrons are implemented as a charge neutralizing fluid.…”

Section: Methodsmentioning

confidence: 99%

“…The first models of Martian gas dynamics were Spreiter et al () and Dryer and Heckman (). Since then the number of models capable of simulating the Martian magnetosphere has proliferated greatly, and now includes a variety of magnetohydrodynamic (MHD; Dong et al, ; Harnett & Winglee, ; Ma et al, ; Najib et al, ; Terada et al, ), Hybrid (Boesswetter et al, ; Brecht et al, ; Holmstrom & Wang, ; Jarvinen et al, ; Kallio & Janhunen, ; Modolo et al, ), and test particle (Cravens et al, ; Fang et al, ; Liemohn et al, ) models.…”

Section: Introductionmentioning

confidence: 99%

Comparison of Global Martian Plasma Models in the Context of MAVEN Observations

Egan

Dong

et al. 2018

JGR Space Physics

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Global models of the interaction of the solar wind with the Martian upper atmosphere have proved to be valuable tools for investigating both the escape to space of the Martian atmosphere and the physical processes controlling this complex interaction. The many models currently in use employ different physical assumptions, but it can be difficult to directly compare the effectiveness of the models since they are rarely run for the same input conditions. Here we present the results of a model comparison activity, where five global models (single-fluid MHD, multifluid MHD, multifluid electron pressure MHD, and two hybrid models) were run for identical conditions corresponding to a single orbit of observations from the Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft. We find that low-altitude ion densities are very similar across all models and are comparable to MAVEN ion density measurements from periapsis. Plasma boundaries appear generally symmetric in all models and vary only slightly in extent. Despite these similarities there are clear morphological differences in ion behavior in other regions such as the tail and southern hemisphere. These differences are observable in ion escape loss maps and are necessary to understand in order to accurately use models in aiding our understanding of the Martian plasma environment.

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“…The following simulations were performed using RHybrid (Jarvinen et al 2018), a hybrid global plasma model for planetary magnetospheres. In a hybrid model the ions are treated as macroparticle clouds that are evolved according to the Lorentz equation, while the electrons are treated as a charge neutralizing fluid.…”

Section: Methodsmentioning

confidence: 99%

Stellar influence on heavy ion escape from unmagnetized exoplanets

Egan

Järvinen

Brain

2019

Monthly Notices of the Royal Astronomical Society

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Planetary habitability is in part determined by the atmospheric evolution of a planet; one key component of such evolution is escape of heavy ions to space. Ion loss processes are sensitive to the plasma environment of the planet, dictated by the stellar wind and stellar radiation. These conditions are likely to vary from what we observe in our own solar system when considering a planet in the habitable zone around an M-dwarf. Here we use a hybrid global plasma model to perform a systematic study of the changing plasma environment and ion escape as a function of stellar input conditions, which are designed to mimic those of potentially habitable planets orbiting M-dwarfs. We begin with a nominal case of a solar wind experienced at Mars today, and incrementally modify the interplanetary magnetic field orientation and strength, dynamic pressure, and Extreme Ultraviolet input. We find that both ion loss morphology and overall rates vary significantly, and in cases where the stellar wind pressure was increased, the ion loss began to be diffusion or production limited with roughly half of all produced ions being lost. This limit implies that extreme care must be taken when extrapolating loss processes observed in the solar system to extreme environments.

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Oxygen Ion Energization at Mars: Comparison of MAVEN and Mars Express Observations to Global Hybrid Simulation

Cited by 29 publications

References 47 publications

Influence of the Solar Wind Dynamic Pressure on the Ion Precipitation: MAVEN Observations and Simulation Results

Influence of the Solar Wind Dynamic Pressure on the Ion Precipitation: MAVEN Observations and Simulation Results

Comparison of Global Martian Plasma Models in the Context of MAVEN Observations

Stellar influence on heavy ion escape from unmagnetized exoplanets

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