  The study of the robust features of the magnetosphere is motivated both by
new "whole system" approaches, and by the idea of "space climate" as opposed to
"space weather". We enumerate these features for the AE index, and discuss
whether self-organised criticality (SOC) is the most natural explanation of the
"stylised facts" so far known for AE. We identify and discuss some open
questions, answers to which will clarify the extent to which AE's properties
provide evidence for SOC. We then suggest an SOC-like reconnection-based
scenario drawing on the result of Craig(2001) as an explanation of the very
recent demonstration by Uritsky et al(2001b) of power laws in several
properties of spatiotemporal features seen in auroral images.
