A SOC based avalanche model to study the magnetosphere-ionosphere energy transfer and AE index fluctuations

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Abstract

Magnetosphere-ionosphere energy transfer and AE fluctuations are studied using a cellular automata model of terrestrial magnetosphere based on the concept of self-organised criticality (SOC). The model is a SOC-driven dissipative dynamical system with both spatial and temporal degrees of freedom. The input parameter to this model is derived from the real-time values of solar wind ion density and flow speed data. Both the direction and intensity of the real-time values of the B component of the interplanetary magnetic field (IMF) are the factors controlling the energy injection into the system. The model produces an output series which can be regarded as a mathematical representation of the AE index. The spectral response of the simulated output follows a 1/f power law, demonstrates a breakpoint at f = 0.050 mHz (5.5 hours) having slopes β = 2.2–2.4 for f > f and β = 0.9–1.0 for f < f, the typical characteristics of the natural AE index. The entire 23 solar cycle had been studied using the model. The parameter K plays a significant role in the entire process. K represents the remaining percentage of the released energy from the previous magnetosphere-ionosphere energy transfer, stored in the ionosphere.

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NRIAG Journal of Astronomy and Geophysics
Volume 11, Issue 1
December 2022
Pages 33-47

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