## Abstract

The dayside magnetopause moves closer to the Earth with increasing southward IMF B_{z}. Is the response of magnetopause to solar wind parameters, southward IMF B_{z}, and dynamic pressure D_{p} linear or nonlinear? GOES observations on 6 April 2000 shows that the magnetopause is still outside of geosynchronous orbit even though the southward IMF B_{z} is greater than 25 nT and D_{p} is near 8 nPa. We suggest that the earthward motion of the dayside magnetopause saturates for large southward IMF B_{z}. Magnetosheath encounters observed by GOES satellites during 1999-2000 are used as a database for selecting a functional form of the saturation effect based on the calculations of the modified magnetopause model of Chao et al. [2002]. To obtain a relationship of the threshold of southward IMF B_{z} for saturation occurring as a function of D_{p}, an iteration procedure is used to minimize the false alarm rate (FAR) and maximize the probability of prediction (PoP). The relationship B′_{z} = -8.1 - 12.0 × log (D_{p} + 1) is obtained where B′_{z} is the threshold of IMF B_{z} for saturation. This relationship is applied to a modified Chao et al. [2002] model and the new model is compared against magnetosheath encounters observed by the LANL MPA instruments on 31 March 2001.

Original language | English |
---|---|

Article number | 1104 |

Journal | Journal of Geophysical Research: Space Physics |

Volume | 108 |

Issue number | A3 |

DOIs | |

State | Published - Mar 2003 |

## Keywords

- Encounter
- Geosynchronous orbit
- Magnetopause
- Magnetosheath
- Saturation
- Solar wind