Imaging the Plasma Sheet with Energetic Ions from the POLAR Satellite

Multiple discrete-energy ion features in the inner magnetosphere: 9 February 1998, event

“…decrease in number density) are expected to account for band 6. The concept is similar to that previously proposed by Peterson et al (1998) and Ebihara et al (2001), that is, the migration of spatially varying plasma sheet ions produces the banded ions in the inner magnetosphere. Our calculation indicates that the migration is possible to produce band 6, but not entirely to produce the remain of the bands.…”

“…Our calculation indicates that the migration is possible to produce band 6, but not entirely to produce the remain of the bands. As suggested by Peterson et al (1998) and Ebihara et al (2001), we can monitor remotely the history of the plasma sheet ions by investigating some of the dispersed ion structures. Indeed, a 2-h decrease in the plasma sheet density (or corresponding change in the distribution function) was predicted by our simulation scheme.…”

“…Peterson et al (1998) proposed that plasma sheet ion clusters, isolated in space and time in the magnetotail, migrate sunward under the convection electric field, and form the multiple ion bands. Fennell et al (1998) performed a particle simulation (Chen et al, 1993) under a time-dependent convection electric field, and suggested that there are two distinct sources of the ions; the ionosphere for the lower energy bands (∼<1 keV) and the near-to-distant plasma sheet for the higher energy bands (∼>1 keV).…”

Multiple discrete‐energy ion features in the inner magnetosphere: Observations and simulations

“…Since we consider only equatorially mirroring particles and our virtual satellites stays in the equatorial plane, we do not attempt to actually reproduce the observation shown in Quiet time convection electric field and corotarion electric fields To date, the reported multiple discrete energy ion features [Fennell et al, 1998;Peterson et al, 1998] from Polar observations have been during quiet times following substorm activity. Our model field is definitely 'quiet' after the injection because our background field is time-independent.…”

Multiple Discrete-Energy Ion Features in the Inner Magnetosphere: Observations and Simulations

“…The above event on Feb. 9, 1998 and other similar events such as on Sept. 3, 1997, which also occurred during a quiet time following a substorm, have been discussed [Fennell et al, 1998;Peterson et al, 1998] but have not been interpreted in terms of particle drift echoes. Here for the first time, we interpret this feature as a result of time-of-flight effects on an ion's drift around the Earth, and also for the first time demonstrate by test-particle simulations that these multiple bands, spanning a large range of L and energy, are ion drift echoes that can be caused by a single injection that is the result of a single fluctuation in the electric and magnetic fields.…”