Paper#: 48
Poster #:
Session Name: Workshop 4B: Tail Instabilities
Room: 200ABC
Day: Tuesday
Time: 3:45-4:10 p.m.
Abstract Title: Is SOC the Simple Unifying Explanation for Substorm and Non- Substorm Dynamics?
PresentSurname: Chapman, S.C.
All Authors: S.C. Chapman
Abstract : Observational evidence for scale free regimes in auroral indices and the distribution of patches of activity in POLAR UVI auroral images have been cited as evidence that internally the coupled solar wind-magnetospheric system is a highly correlated, complex system. This, coupled with the bursty nature of transport in the magnetotail and evidence for scaling in in situ magnetometer data have led to the suggestion that the system is in a (forced) self organized critical state, exhibiting dynamical properties that can be explored with reference to avalanche (sandpile) models as reduced descriptions for the system. A key insight is that the observed statistics of substorms show a characteristic scale whereas there is evidence that the smaller events associated with bursty transport are scale free; consistent with substorms being simply those energy dissipation events in a finite sized SOC system that involve the entire system. If the system is in SOC the precise nature of the instability that initiates either a bursty transport event, or a substorm, does not strongly affect the subsequent net energy release or the degree of predictability (forecastability). An alternative hypothesis is that the internal transport is turbulent and thus scale free whereas substorms represent a distinct process. Methods for distinguishing these and other hypotheses in a quantifiable manner will be discussed.