Engineering topics

Cowley, S. W. H.

Publications and source records attributed to Cowley, S. W. H..

42 records · Page 3

NASA NTRS1985

Electric and magnetic drift of non-adiabatic ions in the earth's geomagnetic tail current sheet

It has been shown recently that nonadiabatic particles in the earth's magnetotail drift across the tail roughly as predicted for adiabatic particles with 90 deg pitch angles. In this paper it is shown that this result implies the existence of an approximate invariant of the motion. Adding the effect of convection associated electric fields, the approximate bounce averaged motion of nonadiabatic particles in the magnetotail can be obtained. Thus the particle motion and energization due to combined magnetic and electric drifts in the magnetotail are easily predicted.

Beard, D. B.↗

NASA NTRS1985

Magnetospheric and ionospheric plasmas; Proceedings of the Ninth Symposium and Topical Meeting, Graz, Austria, June 25-July 7, 1984

Papers are presented on the physics of the magnetosphere-ionosphere connection, with attention given to theory and modeling, auroras, plasma dynamics and irregularities, waves and electron beams, the dynamics of the thermosphere, and planetary plasmas. Plasma circulation in the magnetosphere is also discussed; consideration is given to observations of magnetospheric convection from low altitudes, the structure and properties of the earth's plasmasphere, and the circulation of energetic ions of terrestrial origin in the magnetosphere.

Schmerling, E. R.↗

NASA NTRS1984

Energetic ion regimes in the deep geomagnetic tail - ISEE-3

Bame et al. (1983) have given plasma measurements for two 12-hour intervals and have identified the plasma regions observed during the January 1-March 30, 1983 traversal by the ISEE-3 spacecraft of a previously unexplored part of the distant geomagnetic tail. Attention is presently given to the 35 keV-1.6 MeV energetic ion and magnetic field measurements made by ISEE-3, relating them to the plasma measurements. The plasma sheet is found to be a region of energetic ion enhanced fluxes, with unidirectionally tailored flow. A characterization accounting for these characteristics involves occurrence of reconnection at a neutral line that lies earthward of the spacecraft.

Cowley, S. W. H.↗

NASA NTRS1984

A survey of dayside flux transfer events observed by ISEE 1 and 2 magnetometers

Flux transfer events (FTEs), observed on both the interior and exterior of the dayside magnetopause region by the ISEE 1 and 2 spacecraft, are noted to be a feature of the magnetopause region covered by the spacecraft when the magnetic field in the magnetosheath has a southward component, but not when it is northward. During periods of southward magnetosheath field, the average number and recurrence time of FTE signatures/magnetopause crossing are similar to those observed in the magnetopause interior, implying that the magnetosheath and magnetosphere FTEs are aspects of the same physical phenomenon. It is speculated that FTEs may provide the dominant means of flux transfer required for the driving of geomagnetic disturbances.

Rijnbeek, R. P.↗

NASA NTRS1984

Recent investigations of flux transfer events observed at the dayside magnetopause

The results of the survey of dayside flux-transfer events (FTEs) of Rijnbeek et al. (1984) are summarized. FTEs are a common feature of the dayside magnetopause covered by the ISEE 1 and 2 spacecraft. They occur essentially whenever the magnetosheath magnetic field has a southward component. The properties of FTEs observed in the magnetosheath and in the magnetosphere are similar. FTEs contribute significantly to the flux erosion process at the dayside boundary when the external field has a southward component. Intervals of quasi-steady reconnection occur in close association with observations of FTE signatures. Finally, some remaining questions relating to FTEs are outlined.

Rijnbeek, R. P.↗

NASA NTRS1982

Observations of reverse polarity flux transfer events at the earth's dayside magnetopause

High resolution plasma and magnetic field measurements made by the ISEE 1 and 2 spacecraft have provided the first definitive observations of magnetic reconnection at the dayside boundary, occurring either as a large-scale, quasisteady process enduring on time scales of at least tens of minutes or as a transient process localized in both temporal and spatial extent. Observations of flux transfer events (FTEs) at the earth's dayside magnetopause are presented which have plasma and magnetic field signatures reversed in sign from those previously reported. These FTEs are interpreted in terms of localized and transitory reconnection with the spacecraft located south of the reconnection site. They are associated with a previously reported interval of quasisteady reconnection which is similarly located, indicating that a close physical connection exists between the two processes.

Rijnbeek, R. P.↗