Uberoi, C (1991) Comment on “Southward magnetic field in the neutral sheet produced by wavy motions Propagating in the dawn‐dusk direction”. In: Geophysical Research Letters, 18 (3). pp. 479-480.Full text not available from this repository.
In a recent paper Nakagawa and Nishida  have suggested that wavy motions of the neutral sheet can be generated by the Kelvin‐Helmholtz instability if the dawn‐dusk flow of only several tens of km/s is present. However, their mathematical analysis is based on the choice of particular magnetic field directions in the three regions consisting of north, south lobes and the neutral sheet. In an earlier paper Uberoi  discussed the Kelvin‐Helmholtz instability of a similar structured plasma layer without any assumptions either on velocity field directions or on the magnetic field directions, thus pointing out the angle effect due to variation in magnetic field directions on the instability criterion. The relevance of these results to the problem of wavy motions of the neutral sheet are pointed out. In particular it is found that when the y‐component of the magnetic field in each lobe is taken into consideration the Kelvin‐Helmholtz instability can be exicted only when the dawn‐dusk flow is of several hundreds of km/s a order of ten higher than that arrived in the analysis by Nakagawa and Nishida .
|Item Type:||Journal Article|
|Additional Information:||Copyright of this article belongs to American Geophysical Union.|
|Department/Centre:||Division of Physical & Mathematical Sciences > Astronomy and Astrophysics Programme|
|Date Deposited:||30 Nov 2010 10:34|
|Last Modified:||30 Nov 2010 10:34|
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