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Corrigendum to “Hydrostatic equilibrium and convective stability in the plasmasphere”: [Journal of Atmospheric and Solar-Terrestrial Physics 61 (1999) 867–878]

✍ Scribed by J.F. Lemaire


Publisher
Elsevier Science
Year
2001
Tongue
English
Weight
64 KB
Volume
63
Category
Article
ISSN
1364-6826

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✦ Synopsis


This ÿgure replaces Fig. 4 of p. 872 in the article referred above. Although the instability thresholds are the same in both ÿgures, the shadings have been corrected for L ¿ L0 = 6:6: The new ÿgure conÿrms that a corotating protonosphere in hydrostatic=barometric equilibrium becomes convectively unstable beyond this equatorial distance (i.e. geosynchronous orbit).

Beyond this radial distance, both pure interchange plasma motions (as described by Gold, 1959; Tserkovnikov, 1960) and quasi-interchange plasma motions (as described by Newcomb, 1961) are unstable for any (negative) density slope=gradient larger than the values given by the dashed and dotted lines, respectively: i.e. when the density scale height within an embedded volume element is smaller than the threshold values corresponding to the dashed and dotted lines, respectively.

The legend of this new Fig. 4 is unchanged, as well as the text of the article itself, except for a typographical error on p. 871 (line 7 in the column of the right-hand side) where -d ln m=d z should be replaced by -d ln n=d z.

From this new ÿgure it is clear that the geosynchronous distance is a crossover location where any negative density slope becomes convectively unstable with respect to both convective instabilities in a corotating protonosphere or plasmasphere in hydrostatic=barometric equilibrium. Note that the e ect of B-ÿeld line curvature on these stability criteria will be addressed in a paper currently in preparation.