Joint-Multifractal Analysis of High and Low Latitude Magnetospheric Dynamics.

The dynamics of the Earth's magnetosphere are a tremendously complex system that exhibit nonlinear dynamics in response to variations in the solar wind and interplanetary magnetic field. It has been amply demonstrated in the past that scale-invariant processes define magnetospheric dynamics as measured by geomagnetic indices. Forced and/or Self Organized Criticality, a term coined by T.S. Chang in the 90s, describes the plasma dynamics in the magnetospheric tail region. The multifractal structure of the variations of geomagnetic indices is another distinctive feature of the Earth's magnetospheric response.  Here, we use the joint multifractal measures approach first proposed by Meneveau et al. (1990) and low and high latitude geomagnetic indices  (AE, AL, Sym-H, Asy-H ,etc) to examine the link between the intermittency degrees of high and low latitude dynamics. The findings are examined in regard to the coupling of storms and substorms.