Oxygen ion escape from Venus in a global hybrid simulation: role of the ionospheric O&amp;lt;sup&amp;gt;+&amp;lt;/sup&amp;gt; ions

Järvinen, R.; Kallio, Esa; Janhunen, P.; Barabash, S.; Zhang, T. L.; Pohjola, Valter; Sillanpää, I.

doi:10.5194/angeo-27-4333-2009

Cited by 32 publications

(45 citation statements)

References 32 publications

(34 reference statements)

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“…The clear asymmetry of the ion acceleration with respect to the plasma sheet/current sheet may result from a combination of the solar wind motional electric field direction (e.g. Kallio et al 2006;Järvinen et al 2009), and a tailward evolving pickup process (e.g. .…”

Section: Mass-loaded Ion Energizationmentioning

confidence: 99%

“…The VSE coordinate system takes preference not only on the morphology of the solar wind interaction with Venus, but also with regard to the ionospheric ion acceleration processes, the ion pickup process (see e.g. Kallio et al 2006;Järvinen et al 2009). The ionospheric ion acceleration and outflow follow a distinct "North-South" asymmetry (VSE).…”

Section: Plasma Escape From Mars and Venusmentioning

confidence: 99%

“…Publications on non-thermal (Nagy et al 2004). (b) Diagram illustrating the energization and average flow of ionospheric plasma escape based on recent ASPERA3 measurements from Mars Express plasma escape derived from simulations spans over two decades (Brecht and Ferrante 1991;Brecht et al 1993;Ma et al 2002;Kallio and Janhunen 2002;Järvinen et al 2009;Terada et al 2009). Simulation results offer large differences in plasma escape rates.…”

Section: Introductionmentioning

confidence: 99%

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Ion Acceleration and Outflow from Mars and Venus: An Overview

Lundin

2011

Space Sci Rev

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Solar wind forcing of Mars and Venus results in outflow and escape of ionospheric ions. Observations show that the replenishment of ionospheric ions starts in the dayside at low altitudes (≈300-800 km), ions moving at a low velocity (5-10 km/s) in the direction of the external/ magnetosheath flow. At high altitudes, in the inner magnetosheath and in the central tail, ions may be accelerated up to keV energies. However, the dominating energization and outflow process, applicable for the inner magnetosphere of Mars and Venus, leads to outflow at energies ≈5-20 eV.The aim of this overview is to analyze ion acceleration processes associated with the outflow and escape of ionospheric ions from Mars and Venus. Qualitatively, ion acceleration may be divided in two categories:(a) Modest ion acceleration, leading to bulk outflow and/or return flow (circulation). (b) Acceleration to well over escape velocity, up into the keV range.In the first category we find a processes denoted "planetary wind", the result of e.g. ambipolar diffusion, wave enhanced planetary wind, and mass-loaded ion pickup. In the second category we find ion pickup, current sheet acceleration, wave acceleration, and parallel electric fields, the latter above Martian crustal magnetic field regions. Both categories involve mass loading. Highly mass-loaded ion energization may lead to a low-velocity bulk flow-A consequence of energy and momentum conservation. It is therefore not self-evident what group, or what processes are connected with the low-energy outflow of ionospheric ions from Mars.Experimental and theoretical findings on ionospheric ion acceleration and outflow from Mars and Venus are discussed in this report.

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Section: Mass-loaded Ion Energizationmentioning

confidence: 99%

Section: Plasma Escape From Mars and Venusmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Ion Acceleration and Outflow from Mars and Venus: An Overview

Lundin

2011

Space Sci Rev

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“…It is based on a hybrid-kinetic platform developed over the last fifteen years by our team to study the solar wind action on the plasma environment of various solar system bodies (Kallio & Janhunen 2002, 2003Kallio et al 2006a;Kallio & Jarvinen 2012;Jarvinen & Kallio 2014;Dyadechkin et al 2015, and references therein). Models at Mars and Venus (Kallio et al 2006bJarvinen et al 2009) or Titan (Sillanpää et al 2007) have given new insights regarding in-situ observations. The present model is the adaptation of this 3D hybrid platform to a cometary environment.…”

Section: A New Global 3d Hybrid Modelmentioning

confidence: 99%

Hybrid modelling of cometary plasma environments

Wedlund

Alho

Gronoff

et al. 2017

A&A

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Context. The ESA/Rosetta mission made it possible to monitor the plasma environment of a comet, from near aphelion to perihelion conditions. To understand the complex dynamics and plasma structures found at the comet, a modelling effort must be carried out in parallel. Aims. Firstly, we present a 3D hybrid model of the cometary plasma environment including photoionisation, solar wind charge exchange, and electron ionisation reactions; this model is used in stationary and dynamic conditions (mimicking the solar wind variations), and is thus especially adapted to a weakly outgassing comet such as 67P/Churyumov-Gerasimenko, the target of the ESA/Rosetta mission. Secondly, we use the model to study the respective effects of ionisation processes on the formation of the dayside macroscopic magnetic and density boundaries upstream of comet 67P in perihelion conditions at 1.3 AU. Thirdly, we explore and discuss the effects of these processes on the magnetic field line draping, ionisation rates, and composition in the context of the Rosetta mission. Methods. We used a new quasi-neutral hybrid model, originally designed for weakly magnetised planetary bodies, such as Venus, Mars, and Titan, and adapted here to comets. Ionisation processes were monitored individually and together following a probabilistic interaction scheme. Three-dimensional paraboloid fits of the bow shock surface, identified for a magnetosonic Mach number equal to 2, and of the cometopause surface, were performed for a more quantitative analysis. Results. We show that charge exchange and electron ionisation play a major role in the formation of a bow shock-like structure far upstream, while photoionisation is the main driver at and below the cometopause boundary, within 1000 km cometocentric distance. Charge exchange contributes to 42% of the total production rate in the simulation box, whereas production rates from electron ionisation and photoionisation reach 33% and 25%, respectively. We also discuss implications for Rosetta's observations, regarding the detection of the bow shock and the cometopause.

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“…The neutral atmosphere may be represented by a separate atmosphere/thermosphere model that is coupled to the multispecies/multifluid MHD solver. If the ion gyroradius becomes comparable with the typical length scales due to the weak magnetic field, one may need to switch to Hall MHD ), or in some cases fluid solvers may not be appropriate at all, and global hybrid/kinetic models are needed (e.g., Jarvinen et al 2009;Kallio et al 2010;Brecht and Ledvina 2012), for example to model heavy ion escape. Mercury represents a unique challenge, being physically small but magnetised and without a significant atmosphere (Omidi et al 2006).…”

Section: Using Simulations To Accurately Capture Magnetosphere Structmentioning

confidence: 99%

What Controls the Structure and Dynamics of Earth’s Magnetosphere?

et al. 2014

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Unlike most cosmic plasma structures, planetary magnetospheres can be extensively studied in situ. In particular, studies of the Earth's magnetosphere over the past few decades have resulted in a relatively good experimental understanding of both its basic structural properties and its response to changes in the impinging solar wind. In this article we provide a broad overview, designed for researchers unfamiliar with magnetospheric physics, of the main processes and parameters that control the structure and dynamics of planetary magnetospheres, especially the Earth's. In particular, we concentrate on the structure and dynamics of three important regions: the bow shock, the magnetopause and the magnetotail. In the final part of this review we describe the current status of global magnetospheric modelling, which is crucial to placing in situ observations in the proper context and providing a better understanding of magnetospheric structure and dynamics under all possible input conditions. Although the parameter regime experienced in the solar system is limited, the plasma physics that is learned by studying planetary magnetospheres can, in principle, be translated to more general studies of cosmic plasma structures. Conversely, studies of cosmic plasma under a wide range of conditions should be used to understand Earth's

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Oxygen ion escape from Venus in a global hybrid simulation: role of the ionospheric O<sup>+</sup> ions

Cited by 32 publications

References 32 publications

Ion Acceleration and Outflow from Mars and Venus: An Overview

Ion Acceleration and Outflow from Mars and Venus: An Overview

Hybrid modelling of cometary plasma environments

What Controls the Structure and Dynamics of Earth’s Magnetosphere?

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