Thin current sheets in the magnetotail during substorms: CDAW 6 revisited
- Finnish Meteorological Institute, Helsinki (Finland)
- NASA Goddard Space Flight Center, Greenbelt, MD (United States)
- Johns Hopkins Univ., Laurel, MD (United States); and others
The global magnetic field configuration during the growth phase of the CDAW 6 substorm is modeled using data from two suitably located spacecraft and temporally evolving variations of the Ysyganenko magnetic field model. These results are compared with a local calculation of the current sheet location and thickness carried out by McPherron et al. and Sanney et al. Both models suggest that during the growth phase the current sheet rotated away from its nominal location, and simultaneously thinned strongly. The locations and thicknesses obtained from the two models are in good agreement. The global model suggests that the peak current density is {approximately}120 nA/m{sup 2}, and that the cross-tail current almost doubled its intensity during this very strong growth phase. The global model predicts a field configuration that is sufficiently stretched to scatter thermal electrons, which may be conducive to the onset of ion tearing in the tail. The electron plasma data further support this scenario, as the anisotropy present in the low-energy electrons disappears close to the substorm onset. The electron contribution to the intensifying current in this case is of the order of 10% before the isotropization of the distribution. 23 refs., 6 figs.
- OSTI ID:
- 121244
- Journal Information:
- Journal of Geophysical Research, Vol. 99, Issue A4; Other Information: PBD: 1 Apr 1994
- Country of Publication:
- United States
- Language:
- English
Similar Records
Growth-phase thinning of the near-Earth current sheet during the CDAW 6 substorm
Dynamics of plasma, energetic particles, and fields near synchronous orbit in the nighttime sector during magnetospheric substorms