Plasma sheet climatology: Geotail observations and LFM model comparisons

We present a statistical comparison of plasma sheet properties from Geotail measurements and from the Lyon–Fedder–Mobarry (LFM) global magnetohydrodynamic (MHD) model. We compare more than three years of Geotail data with 10 consecutive days of simulation results driven by real solar wind data. Both studies have statistically similar solar wind inputs and a plasma sheet definition that follows from criteria that are widely used in the literature. We map the average plasma pressures, fields, and flows as functions ofXY(GSM) position within the equatorial plasma sheet. The comparisons show a persistent dawn–dusk asymmetry in the statistical patterns of plasma flows and electric fields in both the Geotail and the simulation results. Geotail observes a less rapid fall-off of thermal pressure with downtail distance than is seen in the simulation. The Geotail dataset suffers from an orbital bias, but we show the dawn–dusk asymmetry persists after accounting for the bias. Overall, our study finds similar statistical plasma pressures, magnetic pressures, and perpendicular flows in Geotail measurements, and the LFM MHD regions of the plasma sheet