Ring current decay time model during geomagnetic storms: a simple analytical approach
The ring current growth and decay, characterized by the <I>D<sub>st</sub></I> index, has been studied for thirty years using the Burton et al. (1975) equation. The original formula is based on the restriction of the DPS (Dessler, Parker, and Schoppke) theorem and assuming a...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2008-09-01
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| Series: | Annales Geophysicae |
| Online Access: | https://www.ann-geophys.net/26/2543/2008/angeo-26-2543-2008.pdf |
| Summary: | The ring current growth and decay, characterized by the <I>D<sub>st</sub></I>
index, has been studied for thirty years using the Burton et al. (1975) equation. The original formula is based on the restriction
of the DPS (Dessler, Parker, and Schoppke) theorem and assuming a
constant decay time of particles. The decay time scale is
important because the energy injection rate cannot be determined
it without the knowledge of this parameter.
In a previous work, instead of using a constant value, we introduced
the decay time of particles in the energy rate balance equation
as a continuous function of the absolute value of the pressure
corrected <I>D<sub>st</sub></I> index to avoid the reported discontinuities
determining it. Here, based on the DPS restriction,
we extend our previous empirical work to obtain analytically the proposed continuous function considering
losses due to a global resistive force as a product of
viscous-like, and other related dissipation processes. We test our
model predicting <I>D<sub>st</sub></I> for a couple of specific storm events and
also comparing our results with forecasts of a good reference
model appeared in the literature. |
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| ISSN: | 0992-7689 1432-0576 |