# [PEM13-P23] Meridional distributions of proton plasma and pressure-driven currents in the nightside inner magnetosphere: Arase observations

Keywords:meridional distributions, plasma pressure, pressure-driven currents, Arase satellite

^{*}< -40 nT) using ion measurements covering energy range of 10–180 keV by the Arase satellite. Because the Arase satellite has a large inclination orbit of 31

^{°}, it covers the absolute value of magnetic latitude (|MLAT|) range of 0–40

^{°}and the radial distance of < 6 Re. We find that the plasma pressure decreases significantly with MLAT. The plasma pressure on the same

*L*

^{*}shell at 30

^{°}<|MLAT|<40

^{°}is about 10–60% of that at 0

^{°}<|MLAT|<10

^{°}, and the percentage of decrease is larger on lower L

^{*}shells. The pressure anisotropy which is defined by the perpendicular pressure divided by the parallel pressure decreases with radial distance and shows a weak dependence on |MLAT|. The magnitude of the plasma beta at 30

^{°}<|MLAT|<40

^{°}is one or two order smaller than that at 0

^{°}<|MLAT|<10

^{°}. The relative plasma pressure distribution predicted from the magnetic strength and anisotropy is roughly consistent with the observed plasma pressure for

*L*

^{*}=3.5–5.5. The azimuthal pressure-gradient current derived from the plasma pressure distribution spreads over ~-20

^{°}|MLAT|, while the curvature current is limited in ~0–10

^{°}|MLAT|. We suggest that the latitudinal dependences should be taken into account when considering a temporal evolution of ring current particles from

*L*distributions of successive orbits.