Imaging the plasma sheet from ionospheric observations
Contribution to Book
Density, Particle precipitation, Plasma sheet, Pressure, Quiet time plasma sheet, Solar wind entry into plasma sheet, Temperature
It is likely that after the THEMIS and MMS missions terminate, there will be no satellite dedicated to observing the plasma sheet for a long time. On the other hand, there is an abundance of low Earth orbit (LEO) satellites in the ionosphere. A method for inferring plasma sheet ion temperatures, densities, and pressures from ionospheric observations at LEO is reviewed. To illustrate the power of this technique, examples in case and statistical studies are presented. For the case study, particle precipitation data from five DMSP satellites from 1997 May 25 are used to construct a 2D equatorial ion pressure profile in the plasma sheet. For the statistical study, DMSP particle precipitation data for the entire year of 1992 are used to construct (1) quiet time 2D equatorial plasma sheet ion temperature, density, and pressure profiles and (2) 2D equatorial plasma sheet ion density and temperature for southward and northward interplanetary magnetic field (IMF) and equatorward isotropy boundary (b2i) > 64° (Kp < ∼3). The quiet time plasma sheet temperature, density, and pressure profiles are consistent with the E × B and the gradient/curvature motions of ions originating from the deep tail and low latitude boundary layer (LLBL). During periods of northward IMF, cold dense ions can be found plentifully along the plasma sheet flanks. Observations suggest that the entry mechanism is generally more effective on the dawn flank than at dusk flank and requires a timescale of 10 h. During periods of southward IMF, the presence of these cold dense ions is noticeably diminished, especially at the dusk flank where the density peak is less discernable. These cold dense ions have been previously interpreted in terms of solar wind or magnetosheath ion entry into the plasma sheet from the magnetopause flanks.
Understanding the Space Environment through Global Measurements
Yaireska Colado-Vega, Dennis Gallagher, Harald Frey, Simon Wing
Wing, Simon and Johnson, Jay R., "Imaging the plasma sheet from ionospheric observations" (2022). Faculty Publications. 4279.