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Covey, D. N.

Publications and source records attributed to Covey, D. N..

Magnetic field configuration of the heliosphere in interstellar space

An improved model of the heliospheric magnetic field configuration is presented by including a uniform interstellar magnetic field and by adopting different values for a few magnetic field parameters. All the basic expressions for the magnetic field components remain the same as in Akasofu et al. (1980). In the magnetic arcade field, the magnetic field of the spherical dipoles is changed from 500 to 50 G. In the field of an extensive current disk around the sun lying in the ecliptic plane, the solar current disk extends from a distance of 1.5 solar radii instead of 10 solar radii. A uniform and southward directed interstellar magnetic field of 0.22 gamma is included. The total magnetic field configuration is constructed for the northward and southward orientation of the solar dipole field.

Akasofu, S.-L.↗

Equatorward shift of the cusp during magnetospheric substorms

The equatorward shift of the midday part of the auroral oval (the cusp region) during the expansion phase of magnetospheric substorms is reexamined. A magnetospheric model developed by Akasofu and Corrick (1980) is used, which is constructed by using the earth's dipole field, an image dipole field of the earth and 40 bisected circular loops. A new dayside current system represented by six current loops separated by 15 deg in longitude, each carrying 100 KA, is added to this model. For a total current of .6 MA, the latitude of the cusp shifts equatorward by 1.8 deg; for a current of 1.8 MA, the cusp location shifts by more than 5 deg. Thus, the magnetic field of an enhanced dynamo current is the dayside boundary layer and of the connected circuit can account for the observed equatorward shift of the cusp region.

Akasofu, S.-I.↗