Task 3: Modeling of the (past) lunar core dynamo

The objective of this task is to propose a lunar dynamo scenario that can account for the lunar surface field evolution provided by task 1 in terms of chronology and surface field intensity. To do so, we need to know how a flow is driven in the liquid core, and to characterize this flow. For certain scenarii, this can be done by assuming the liquid core boundary to be spherical, which allows the use of the very efficient spectral code XHSELLS, whereas for others, more generic methods (e.g. finite elements, as in the commercial software COMSOL) need to be used, at the cost of efficiency. In this latter case, experimental studies allow to complement this lost efficiency. Second, we need to go beyond the usual but weak power argument to assess the possibility of a dynamo excited by these flows. In this task, we will also investigate why the dynamo began and stopped, which is a key question when comparing to magnetic data.

Participants are D. Cébron, N. Schaeffer, M. Le Bars, B. Favier, M. Wieczorek.