Mod\'elisation Magn\'etohydrodynamique

TL;DR

This paper introduces CLOVIS, a computational code modeling ionospheric perturbations using magnetohydrodynamic equations solved with Godunov finite volume methods, validated against analytical and experimental test cases.

Contribution

Development and validation of CLOVIS, a new physics code for simulating ionospheric dynamics with advanced numerical methods.

Findings

CLOVIS successfully models ionospheric phenomena.

Numerical results agree with analytical and experimental data.

Code performance is validated through comparison with other models.

Abstract

To better understand the occurrence and evolution of ionospheric perturbations, the CEA develops CLOVIS, a physical code that describes the dynamics of neutrals and ionized particles in the Earth's magnetic field. CLOVIS solved the hydrodynamic equations (Euler's equations) and magnetohydrodynamic equations using the Godunov finite volume method with Riemann solvers of Roe and type HLL (Euler-Maxwell equations). The validation step, which finalized the development phase of each solver, allows comparison of CLOVIS' numerical results with test-cases, the solutions to which are known analytically or experimentally. CLOVIS results are typically compared quantitatively, if possible, or qualitatively, in most cases, with those of other codes. -- Pour comprendre l'apparition et l'\'evolution de ph\'enom\`enes ionosph\'eriques, le CEA d\'eveloppe CLOVIS, un code de physique, qui d\'ecrit la dynamique des particules neutres et ionis\'ees dans le champ magn\'etique terrestre. Il utilise la m\'ethode des Volumes Finis de type Godunov avec des solveurs de Riemann de Roe ou de type HLL pour r\'esoudre les \'equations de l'hydrodynamique (\'equations d'Euler), aussi bien que pour r\'esoudre celles de la magn\'etohydrodynamique (\'equations d'Euler- Maxwell). L'\'etape de validation de CLOVIS, qui finalise la phase de d\'eveloppement de chaque solveur, permet de comparer les r\'esultats du code \`a des cas-tests dont les solutions sont connues, soit de mani\`ere analytique, soit de mani\`ere exp\'erimentale. A d\'efaut, on compare, si possible quantitativement, mais souvent qualitativement, le r\'esultat de CLOVIS \`a ceux d'autres codes.