On a new process for cusp irregularity production
Two plasma instability mechanisms were thought until 2007 to dominate the formation of plasma irregularities in the F region high latitude and polar ionosphere; the gradient-drift driven instability, and the velocity-shear driven instability. The former mechanism was accepted as accounting for p...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2008-09-01
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| Series: | Annales Geophysicae |
| Online Access: | https://www.ann-geophys.net/26/2871/2008/angeo-26-2871-2008.pdf |
| Summary: | Two plasma instability mechanisms were thought until 2007 to dominate the
formation of plasma irregularities in the F region high latitude and polar
ionosphere; the gradient-drift driven instability, and the velocity-shear
driven instability. The former mechanism was accepted as accounting for
plasma structuring in polar cap patches, the latter for plasma structuring
in polar cap sun aligned arcs. Recent work has established the need to
replace this view of the past two decades with a new patch plasma structuring
process (not a new mechanism), whereby shear-driven instabilities first
rapidly structure the entering plasma, after which gradient drift
instabilities build on these large "seed" irregularities. Correct modeling
of cusp and early polar cap patch structuring will not be accomplished
without allowing for this compound process. This compound process explains
several previously unexplained characteristics of cusp and early polar cap
patch irregularities. Here we introduce additional data, coincident in time
and space, to extend that work to smaller irregularity scale sizes and
relate it to the structured cusp current system. |
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| ISSN: | 0992-7689 1432-0576 |