EarthRef.org Reference Database (ERR)
Development and Maintenance by the EarthRef.org Database Team

Detailed Reference Information
Wright & Garman 1998
Wright, A.N. and Garman, A.R. (1998). MHD wave coupling in the geomagnetic tail with field-aligned density variations. Journal of Geophysical Research 103: doi: 10.1029/97JA02865. issn: 0148-0227.

The normal MHD modes of the tail lobe are calculated for a simple model that is stratified in z. An important feature of our equilibrium field is that it may be tilted at an arbitrary angle (&thgr;) to the antisunward direction, i.e., B=B(cos &thgr;,0,sin &thgr;). When &thgr;=0, the familiar singular second-order equation of Southwood [1974> is recovered. When &thgr;≠0, the system is governed by a nonsingular fourth-order equation. Hansen and Harrold [1994> (hereafter HH) considered exactly this system and concluded that (for &thgr;≠0) energy was no longer absorbed by a singularity but rather over a thickened boundary layer across which the time-averaged Poynting flux (⟨Sz⟩) changed. Our results are not in agreement with those of HH. We find ⟨Sz is independent of z and find no evidence of boundary layers, even for &thgr; as small as 10-6 rad. Our solutions still demonstrate strong mode conversion from fast to Alfv¿n modes at the resonant position, but the small component of Alfv¿n speed in the z⁁ direction permits the Alfv¿n waves to transport energy away from this location and prevents the continual accumulation of energy there. The implications for MHD wave coupling in realistic tail equilibria are discussed. ¿ 1998 American Geophysical Union

BACKGROUND DATA FILES

Abstract

Keywords
Magnetospheric Physics, Magnetospheric configuration and dynamics, Magnetospheric Physics, Magnetotail, Magnetospheric Physics, MHD waves and instabilities, Space Plasma Physics, Kinetic and MHD theory
Journal
Journal of Geophysical Research
http://www.agu.org/journals/jb/
Publisher
American Geophysical Union
2000 Florida Avenue N.W.
Washington, D.C. 20009-1277
USA
1-202-462-6900
1-202-328-0566
service@agu.org
Click to clear formClick to return to previous pageClick to submit