FUTURE WORKS AND SOME QUESTIONS

The problem of inferring the core physics remains one of the most important still open question that can be addressed by helioseismology. It is therefore very important, as a first step, to be sure that different `inverters' using different inverse methods can reach similar conclusions when they use the same datasets. This was the goal of this work in collaboration between `inverters' within the GOLF team and we have shown that the different approaches of the inversion are coherent. After this preliminary work several questions need to be addressed, for example:

• Can we obtain reliable results below 0.2R with actual datasets?
• How the results in the core are sensitive to the data used for medium l splittings?
• Can we explain the differences between the results obtained with different data by a systematic bias in some splitting measurements or by underestimated errors in a few number of individual splittings?
• Can these results (obtained with inverse methods) be confirmed by using forward methods often used for the core rotation problem [Charbonneau et al.1998,Gizon1998]?