Pantellini, Griton & Varella 2015

Rarefaction and compressional standing slow mode structures in Mercury’s magnetosheath: 3D MHD simulations

Authors: Pantellini, Filippo; Griton, Léa; Varela, Jacobo
Publication: Planetary and Space Science, Volume 112, p. 1-9. (P&SS Homepage)

Keywords: MHD simulations, Mercury, Magnetosphere, Slow mode waves
Abstract Copyright: (c) 2015 Elsevier Ltd
DOI: 10.1016/j.pss.2015.04.007

Abstract
We show that slow mode compressional fronts form upstream of the day side magnetopause in MHD simulations of Mercury’s magnetosphere. The strongest compressional fronts are located upstream of the magnetopause with strong magnetic shear. Compressional fronts are crossed by magnetic field lines connecting the interplanetary magnetic field and the planet’s intrinsic field, their role is to bend the magnetic field in the magnetosheath towards the magnetopause. Besides these compressional fronts, already observed in space and theoretically discussed by various authors for the case of the Earth, we observe the formation of a slow mode standing rarefaction wave spatially growing over a substantial fraction of the distance between the bow shock and the magnetopause. The slow mode source region for the rarefaction waves is located in the magnetosheath, near the bow shock’s nose. The generated standing rarefaction waves, however, form even at large distances from the source region along the magnetospheric flanks. They fine-tune the magnetic field line draping and plasma flow around the magnetopause. In ideal MHD the magnetospheres of Mercury, the Earth and the giant planets do closely resemble each other, we therefore expect the mentioned slow mode structures not to be specific to Mercury.

See the paper for the legend of this figure.  (c) 2015 Elsevier Ltd

EGU 2016

Identification of standing MHD modes in MHD simulations of planetary magnetospheres. Application to Mercury.

Authors: Griton, Léa; Pantellini, Filippo; Moncuquet, Michel
Affiliation: AA(Observatoire de Paris-CNRS, LESIA, Meudon, France), AB(Observatoire de Paris-CNRS, LESIA, Meudon, France), AC(Observatoire de Paris-CNRS, LESIA, Meudon, France)
Publication: EGU General Assembly 2016, held 17-22 April, 2016 in Vienna Austria, id. EPSC2016-14858

Abstract
We present 3D simulations of the interaction of the solar wind with Mercury’s magnetosphere using the magnetohydrodynamic code AMRVAC. A procedure for the identification of standing MHD modes has been applied to these simulations showing that large scale standing slow mode structures may exist in Mercury’s magnetosheath. The identification is mostly based on relatively simple approximate analytical solutions to the old problem of determining the family of all standing linear plane MHD waves in a flowing plasma. The question of the identification of standing slow mode structures using in situ measurements such as the future BepiColombo MMO mission to Mercury will be discussed as well.

MOP 2017

Magnetohydrodynamics (MHD) simulations of the interaction of the solar wind with Saturn and Uranus

Authors: Léa Griton, Filippo Pantellini, Michel Moncuquet
(poster)

Publication: Magnetospheres of Outer Planets (MOP) conference in Uppsala, Sweden – 12 – 16 June 2017

Abstract

We present 3D magnetohydrodynamics (MHD) simulations (on a spherical grid) of the interaction of the solar wind with a fast rotating magnetized planet, with arbitrary orientation of magnetic and spin axis. The large-scale flow in fast-rotating planets’ magnetosphere – which is the case of the four outermost planets – results from both the solar wind interaction and the planetary rotation and is described here for different orientations of the interplanetary magnetic field. We present in particular the effects of the fast rotation of the planet on the configuration of the planet-connected magnetic field lines and on the flow dynamics. We run the MPI-AMRVAC code, adapted for this kind of interaction, to the magnetosphere of Saturn and possibly to the case of Uranus.

 

Crédits photo : MOP 2017

EGU 2017

MHD simulations of fast-rotating planetary magnetospheres

 

Authors: Griton, Léa; Pantellini, Filippo
Affiliation: AA(LESIA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universités, UPMC Univ. Paris 06, Univ. Paris Diderot, Sorbonne Paris Cité lea.griton@obspm.fr), AB(LESIA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universités, UPMC Univ. Paris 06, Univ. Paris Diderot, Sorbonne Paris Cité lea.griton@obspm.fr)

Publication: 19th EGU General Assembly, EGU2017, proceedings from the conference held 23-28 April, 2017 in Vienna, Austria., p.7481

Abstract

We present 3D magnetohydrodynamics (MHD) simulations of the interaction of a supersonic plasma (e.g. the solar wind) with a fast-rotating magnetized spherical body (e.g. the magnetosphere of a giant planet of the Solar System). For given solar wind conditions, the structure of the magnetosphere strongly depends on the orientation of the magnetic axis and the planet spin axis, but also on the ratio of the time required for an Alfvén wave to reach the magnetopause from the planet and the planet rotation period. The effects on the Dungey and Vasyliunas cycles will be discussed.

EPSC 2017

MHD simulations of the interaction of the solar wind with a fast-rotating planet (e.g. Saturn or Uranus)

Authors: Griton, L.; Pantellini, F.
Affiliation: AA(CNRS – Observatoire de Paris, Meudon, France), AB(CNRS – Observatoire de Paris, Meudon, France)
Publication: European Planetary Science Congress 2017, held 17-22 September, 2017 in Riga Latvia, id. EPSC2017-792

Abstract
We present 3D magnetohydrodynamics (MHD) simulations (on a spherical grid) of the interaction of the solar wind with a fast rotating magnetized planet, with arbitrary orientation of magnetic and spin axis. The large-scale flow in fast-rotating magnetospheres (e.g. the giant planets of the solar system) is described here for different orientations of the interplanetary magnetic field. We present in particular the effects of rotation on the configuration of the planet-connected magnetic field lines and on the flow pattern. We adapted the MPI-AMRVAC code to allow for any possible orientation of spin and magnetic axis using a background/residual decomposition of the magnetic field. The Saturn-like case is briefly discussed.

 

AGU Fall Meeting 2017

MHD simulations of the interaction of the Solar Wind with fast-rotating planetary magnetospheres using a time-dependant background/residual decomposition of the magnetic field

Authors : Griton, L. S. ; Pantellini, F. G. E. ; Moncuquet, M.

Affiliation :  AA(LESIA, CNRS, Observatoire de Paris, Meudon, France lea.griton@obspm.fr), AB(LESIA, CNRS, Observatoire de Paris, Meudon, France filippo.pantellini@obspm.fr), AC(LESIA, CNRS, Observatoire de Paris, Meudon, France Michel.Moncuquet@obspm.fr)

Publication: American Geophysical Union, Fall Meeting 2017, abstract #SM33C-2676

Abstract: We present 3D magnetohydrodynamic (MHD) simulations (on a spherical grid) of the interaction of the solar wind with a fast rotating magnetized planet. We adapted the MPI-AMRVAC code to allow for any possible orientation of spin and magnetic axis using a time-dependant background/residual decomposition of the planetar

y magnetic field. The large-scale flow in fast-rotating magnetospheres (e.g. the giant planets of the solar system) is described here for different orientations of the interplanetary magnetic field (IMF). We present in particular the effects of rotation on the configuration of the planet-connected magnetic field lines and on the flow pattern. The Saturn-like case (no tilt between the spin axis and the magnetic axis) is discussed for northward, southward, eastward and westward (Parker-spiral) IMF, along with Jupiter- and Uranus-like magnetospheres (regarding the respective configurations of the spin axis, magnetic axis, and the direction of the solar wind).

 

 

Pantellini & Griton, 2016

Identification of standing fronts in steady state fluid flows: exact and approximate solutions for propagating MHD modes

Authors: F. Pantellini and L. Griton

DOI: 10.1007/s10509-016-2921-y

Journal: Astrophysics and Space Science, Volume 361, Issue 10, article id.335, 11 pp.

Abstract:

The spatial structure of a steady state plasma flow is shaped by the standing modes with local phase velocity exactly opposite to the flow velocity. The general procedure of finding the wave vectors of all possible standing MHD modes in any given point of a stationary flow requires numerically solving an algebraic equation. We present the graphical procedure (already mentioned by some authors in the 1960’s) along with the exact solution for the Alfvén mode and approximate analytic solutions for both fast and slow modes. The technique can be used to identify MHD modes in space and laboratory plasmas as well as in numerical simulations.

See the paper for the figure’s legend.