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		| Paper: | 
		Tracking Magnetic Nulls in a Simulated Magnetosphere | 
	 
	
		| Volume: | 
		359, Numerical Modeling of Space Plasma Flows: Astronum-2006 | 
	 
	
		| Page: | 
		131 | 
	 
	
		| Authors: | 
		Dorelli, J.C.; Bhattacharjee, A.; Raeder, J. | 
	 
	
	
		| Abstract: | 
		We describe a technique for tracking magnetic nulls in computer simulations of magnetized plasmas. The technique is based on the Greene (1992) algorithm of computing the topological degree of a discretized vector field. We apply the Greene algorithm to a resistive magnetohydrodynamics (MHD) simulation of Earth's magnetosphere. We demonstrate that under generic northward interplanetary magnetic field (IMF) conditions, the large scale topology of the dayside magnetopause is consistent with a null-null separator topology, with the dayside X line extending across the subsolar magnetopause and terminating at two magnetic nulls in the polar cusps. | 
	 
	
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