23–25 mars 2022
Observatoire de Meudon
Fuseau horaire Europe/Paris

The magnetopause discontinuity: a MMS study.

24 mars 2022, 10:00
10m
Amphithéâtre & Salle des séminaires (Observatoire de Meudon)

Amphithéâtre & Salle des séminaires

Observatoire de Meudon

Observatoire de Paris, site de Meudon 5, place Jules Janssen, 92195 Meudon cedex
Oral presentation Astrophysics Talk

Orateur

Giulio Ballerini

Description

The magnetopause boundary seems to escape the general classification of discontinuities since it mixes characteristics of shocks (magnetic field magnitude increase) and those typical for the rotational discontinuities (magnetic rotation), whereas it is very often described as a tangential discontinuity. As, the main issue is the amount of matter/momentum/energy from the solar wind and entering into the magnetosphere, the solution cannot be simply achieved by assuming the discontinuity as strictly tangential, everywhere and at all times. Here we propose to study the magnetopause boundary as a "quasi-tangential" discontinuity, with the normal magnetic component Bn small but not null since even small departures from the standard hypothesis of a zero Bn can lead to noticeable changes in the global properties. In that aim, we look into the MMS database for a large number of magnetopause crossings. For each case we will determine what are the most important features that allow the discontinuity to escape the general classification, i.e. to noticeably change the form of the conservation laws on which the theory of discontinuities is based for non strictly tangential discontinuities. We put a special emphasis on the refined methods that can be
used for determining the spatial gradients from four spacecraft data and on the accuracy that can be attained by these methods.

Field Not in the above

Authors

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