ABSTRACT
This chapter is devoted to planetary dynamos. After reviewing observational facts (Section 5.1), we identify some outstanding problems in planetary dynamo theory (Section 5.2). In the light of the observational evidence, we address the conditions needed for dynamo action (Section 5.3), the possible energy sources for planetary dynamos (Section 5.4), the internal structure of the planets (Section 5.5), and the dynamics of planetary interiors (Section 5.6). We finally review, in Section 5.7, the existing numerical planetary dynamo models.
