GEM: Study of Solar Wind-Magnetosphere-Ionosphere Coupling

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This proposed investigation examines energy and momentum flow across the magnetopause using in-situ observations of magnetic field and plasmas obtained by the ISEE 1 and 2 spacecraft and ground based data from the IGS magnetometer chain. The average potential drop across the magnetosphere when the interplanetary magnetic field is southward will be measured using both the magnetic field normal to the magnetopause surface and the flow velocity along the surface. By repeated individual measurements across the surface, both the region of reconnected field and the total potential drop can be estimated. In order to determine the normal component an accurate model of the 3-D shape of the magnetopause will be derived. The pressure dependence of this model will allow us to test if pressure pulses can cause crater FTE's as has been suggested. When the IMF is northward and reconnection is weak, energy transfer can still take place by wave processes. We will examine the waves present from Pc 3 to Pc 5 periods to determine if significant wave energy flux crosses the boundary. We will examine simultaneous ground based data from the IGS magnetometer chain at 2.5s resolution to determine how this wave energy spreads through the magnetosphere. We will also examine the response of auroral and subauroral zone current systems to dynamic pressure changes. Finally, we will examine each of the boundary layers inside and outside the magnetosphere to determine how each of them depends on solar wind conditions and position on the magnetopause in order to determine what processes are responsible for these boundary layers. In particular we will examine their formation as a function of solar wind conditions.