In this project, we plan to use and extend simulation models to describe the complete interaction of SE (including its different phases: interplanetary shock, sheath, ejecta,…) with Earth’s BS and magnetosheath and apply them to weakly magnetized objects like Mars and Mercury, in order to predict for the first time the consequences of such encounter on the magnetic and atmospheric/exospheric environments of these objects. Our main scientific goals are:

a-     Characterizations of the magnetosphere’s responses to Solar Events.

- How does a magnetosphere react when an interplanetary shock, formed upstream of an ICME, encounters a magnetosphere (induced or intrinsic)? How the planetary BS and magnetopause are impacted?

- What are the respective responses of the magnetosphere to the central part of the SE and to their leading edge (shock + sheath)?

b-    Impacts of Solar Events on the upper atmosphere/exosphere (Mars and Mercury) and their implication on the neutral atmosphere and surface.

-     What are the consequences for the upper atmosphere/ exosphere? Can we identify signatures of such encounter in the exosphere?

-     Are transient events more important in terms of escape than steady state interaction?

c-    Determination of the reconfiguration time scales.

- Are reconfiguration time scales proportional to the effective size of the obstacle?

- What are the typical timescales for the upper atmosphere/exosphere after a magnetic configuration change?

Simulations results will be compared to observations through the CDPP visualization tools to first validate the numerical developments and address the scientific questions of the project. 

Two main numerical and technical challenges are identified in the frame of this proposal:

a-    Modelling an interplanetary shock interaction with a planetary BS. Global investigations of transient events on Mars and Mercury on ion scales are very limited and never been addressed with a kinetic model. This project aims to go further and to perform a systematic study of time-dependent drivers (change of density, speed, interplanetary magnetic field direction and magnitude) and their impact on the magnetospheres and exospheres. We aim to simulate the interaction of an Interplanetary Shock with a planetary magnetosphere.  Similarly, the exospheric model can be run under varying upstream conditions. 

b-    Visualization of large simulated data products and comparison with observations. When investigating transient events, we will have to construct series of snapshots. To track a temporal variation, about 30 to 50 snapshots will be needed to follow the responses of the magnetosphere and exosphere which will represent a large amount of memory. We will analyse these runs using a standardized protocol of exchange of information (1D to 4D data) between visualization tools and simulation database which requires extending existing protocols to time-dependent simulations.

The four-year project is divided in 5 work-packages (WP) closely linked together as presented in figure 3. We first propose to self-consistently simulate a prototype of “realistic” solar events (hereafter SE) in the pristine solar wind, including both its central core and the shock wave preceding it, and to push it and collide with the pre-existing planetary bow shock and environment (WP1). This prototype solar event will be used in the following WP2 to analyze its interaction with the boundaries of terrestrial environment.