| Summary: | Recently, observational evidence for scale free regimes in auroral indices, auroral optical emissions and in-situ magnetic field observations in the earth's geotail, have been cited as evidence that "internally" the coupled solar wind-magnetospheric system exhibits scale free self organised criticality and/or turbulent transport. This in addition with the bursty nature of transport in the magnetosphere as evidenced by BBF's have led to the application of avalanche models to understand magnetospheric dynamics. However, on the average, substorm morphology is understood in terms of a loading -unloading cycle with an applied driver, in which there is also evidence of low dimensionality. We discuss a new avalanche model that is a generalization of the original SOC avalanche model of Bak, Tang and Wiesenfeld to include transport as well as thresholded diffusion. In the model, evolution is bursty and yields scaling regimes but the large scale dynamics is low dimensional and is either one of a family of stable, quasiperiodic loading-unloading cycles or is "intermittent". Intermittent dynamics is associated with the system being close to a (nontrivial) fixed point.
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