Eiichi Sagawa

TL;DR: Immel et al. as discussed by the authors showed that ionospheric densities vary with the strength of nonmigrating, diurnal atmospheric tides that are, in turn, driven mainly by weather in the tropics.

TL;DR: In this article, the authors examined the global characteristics of the nighttime equatorial anomaly (EA) by constructing a constant local time map (LT map), in which pixels within an assigned local time range are extracted from the IMAGE/FUV nightglow images obtained over an observation period of 3 days or more and are put together to compose a global distribution map of emission intensities at that local time.

Abstract: We report observations of the H+, He+, and O+ polar wind ions in the polar cap (>80° invariant latitude, ILAT) above the collision-dominated altitudes (>2000 km), from the suprathermal mass spectrometer (SMS) on EXOS D (Akebono). SMS regularly observes low-energy (a few eV) upward ion flows in the high-altitude polar cap, poleward of the auroral oval. The flows are typically characteristic of the polar wind, in that they are field-aligned and cold (Ti 80° ILAT), the average H+ velocity reached 1 km/s near 2000 km, as did the He+ velocity near 3000 km and the O+ velocity near 6000 km. At Akebono apogee (10,000 km), the averaged H+, He+, and O+ velocities were near 12,7, and 4 km/s, respectively. Both the ion velocity and temperature distributions exhibited a day-to-night asymmetry, with higher average values on the dayside than on the nightside.

TL;DR: The MAP-PACE-IMA experiment on SELENE (Kaguya) has completed its ∼1.5-year observation of low-energy charged particles around the Moon.

TL;DR: In this paper, a longitudinal wave number four pattern in the magnetic latitude and concentration of the F region peak ion density when measured at a fixed local time was found to be persistent over many days around equinox during magnetically quiet conditions close to solar maximum but can be dominated by other processes such as cross-equator winds during other periods.