The cause of storm after effects in the middle latitude D-region

Short-Term Delays in the Occurrence of Mid-Latitude Ionospheric Disturbances Following Other Geophysical and Solar Events.

“…Stated briefly, and as Spjeldvik and Thorne (1975) have shown, electrons injected into the radiation belt at times of geomagnetic substorms gradually move to lower L shells and are subsequently precipitated due to pitch-angle scattering with the resulting absorption in subauroral regions. Some discussion on why geomagnetic activity around midnight and the sunrise period (see Fig.…”

Review of radiation belt relativistic electron losses

“…Under relatively quiet conditions, the two-zone structure of the radiation belts is a result of slow inward radial diffusion in the presence of loss caused by whistlermode scattering (Lyons and Thorne, 1973). Under geomagnetically active conditions, the slot between the radiation belts can be partially filled by enhanced source processes, but the injected electrons subsequently decay by precipitation into the atmosphere (Lyons et al, 1972;Spjeldvik and Thorne, 1975;Abel and Thorne, 1998a,b) over a period of days to weeks (Pfitzer and Winckler, 1968;Meredith et al, 2006a).…”

“…This region can be partially filled with relativistic electrons during large magnetic storms (Frank, 1966;Baker et al, 2004), and the flux at $1 MeV decays over $10-100 days due to resonant interaction with hiss (Selesnick et al, 2003;Meredith et al, 2006a). This loss timescale is much longer than the strong diffusion timescale (Kennel and Petschek, 1966), thus leading to a well defined loss cone distribution (Spjeldvik and Thorne, 1975).…”

Comment on ‘Sunday decreases in magnetospheric VLF wave activity’ by C. G. Park and T. R. Miller

“…Daytime absorption in the 2-to 4-kHz band is typically 10-15 db in the vicinity of Siple station [Helliwell, 1965]. The pronounced variability in D region ionospheric density, which is thought to be caused by radiation belt particle precipitation [e.g., $pjeldvik and Thorne, 1975Thorne, , 1976, will consequently induce changes in the magnitude of signals detected at the ground even without variability in the level of magnetospheric wave power. This together with the stringent requirements for ducted propagation to the ground-based receiver gives little reassurance that the variability in signal amplitude measured at Siple has any direct bearing on the variability of magnetospheric wave power.…”