Modeling the Development of Plasmasphere Ducts and Irregularities With SAMI3/WACCM-X

We show that atmospheric gravity waves can generate plasma ducts and irregularities in the plasmasphere using the coupled SAMI3/WACCM-X model. We find the equatorial electron density is irregular as a function of longitude which is consistent with CRRES measurements (Clilverd et al., 2007, ). We also find that plasma ducts can be generated for L-shells in the range 1.5-3.0 with lifetimes of similar to 0.5 hr; this is in line with observations of ducted VLF wave propagation with lifetimes of 0.5-2.0 hr (Clilverd et al., 2008, ; Singh et al., 1998, ). Electromagnetic plasma waves, known as whistler waves, are observed to propagate in the ionosphere/plasmasphere system where the ionosphere is nominally defined as the partially ionized gas surrounding the earth in the altitude range 90-1,000 km and the plasmasphere is essentially the extension of the ionosphere 1,000s of km into space along closed geomagnetic field lines. Whistler wave propagation has been characterized as ducted and non-ducted. Ducted propagation is guided along the magnetic field by density tubes in which the plasma density is lower or higher than the background plasma. However, the physical processes that generate these ducts has remained unclear. We show that these plasma ducts can be generated by atmospheric gravity waves that perturb the ionosphere and plasmasphere electron density using the coupled SAMI3/WACCM-X model. Atmospheric gravity waves can generate plasma ducts and irregularities in the plasmasphere using the coupled SAMI3/WACCM-X modelThe electron density in the equatorial plasmasphere is irregular as a function of longitudePlasma ducts can be generated for L-shells in the range 1.5-3.0 with lifetimes of 0.5-2.0 hr