Instabilities and Structure in the High-Latitude Ionosphere - The Earth's Ionosphere: Plasma Physics and Electrodynamics - page 536

of elevation angle. The spatial distributions of the phases of the electron advec-
tion term and electron E B velocity for the secondary modes lead to the partial

cancellation of the destabilizing zero-order electron drift, thereby saturating the
Farley-Buneman instability.
Built on these results, Bahcivan and Hysell (2006) proposed a theory for
type 2 (broad) echoes they observed at an angle to the electron drift (Bahci-
van et al., 2005). They propose secondary ion-acoustic structures driven by the
electric fields in primary Farley-Buneman waves. In their model, the wave spectra
broaden with a mean value equal to C s cos

×

θ

.

10.7 Summary

In this chapter we only scratched the surface in the plasma physics of high-
latitude phenomena. We have in some cases been able to export results from
other latitudes, but, in general, the high-latitude regime has added features that
complicate the physics. These problems are likely to keep ionospheric plasma
physics an exciting discipline for the foreseeable future.

References

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