### Abstract

In this paper we unify two approaches to determining magnetopause shape and location from observations by fitting one model simultaneously to both the crossing data and the calculated data of magnetopause flaring angle, to achieve more accurate magnetopause shapes. We prepare two magnetopause models, each of which is an ellipsoid from the subsolar point to the position where the distance of the ellipsoid from the X axis is maximum. The model magnetopause beyond this position is a cylinder attached to the edge of the ellipsoid at this location. This choice of shapes makes it easier to compare our results with earlier work which fit ellipsoids to (only) crossing data. In one of our two models, the focus of the ellipsoid lies at the center of the Earth, whereas in the other it lies at a position determined from fits to the data. We use a statistical criterion (called AIC) that lets us objectively determine which model better fits the data. As a result, we find that a model with an off-center focus better expresses the nature of the observed data. Despite differing mathematical formulations, our model results generally resemble those of Petrinec and Russell [1996]. Consequently, the mathematical expression is not the major reason why these models flare more (less) than the model of Roelof and Sibeck [1993] for very small (large) solar wind dynamic pressure.

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

Article number | 98JA02479 |

Pages (from-to) | 247-261 |

Number of pages | 15 |

Journal | Journal of Geophysical Research: Space Physics |

Volume | 104 |

Issue number | A1 |

Publication status | Published - Jan 1 1999 |

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### All Science Journal Classification (ASJC) codes

- Geophysics
- Forestry
- Oceanography
- Aquatic Science
- Ecology
- Water Science and Technology
- Soil Science
- Geochemistry and Petrology
- Earth-Surface Processes
- Atmospheric Science
- Earth and Planetary Sciences (miscellaneous)
- Space and Planetary Science
- Palaeontology

### Cite this

*Journal of Geophysical Research: Space Physics*,

*104*(A1), 247-261. [98JA02479].

**Magnetopause shape determinations from measured position and estimated flaring angle.** / Kawano, Hideaki; Petrinec, S. M.; Russell, C. T.; Higuchi, T.

Research output: Contribution to journal › Article

*Journal of Geophysical Research: Space Physics*, vol. 104, no. A1, 98JA02479, pp. 247-261.

}

TY - JOUR

T1 - Magnetopause shape determinations from measured position and estimated flaring angle

AU - Kawano, Hideaki

AU - Petrinec, S. M.

AU - Russell, C. T.

AU - Higuchi, T.

PY - 1999/1/1

Y1 - 1999/1/1

N2 - In this paper we unify two approaches to determining magnetopause shape and location from observations by fitting one model simultaneously to both the crossing data and the calculated data of magnetopause flaring angle, to achieve more accurate magnetopause shapes. We prepare two magnetopause models, each of which is an ellipsoid from the subsolar point to the position where the distance of the ellipsoid from the X axis is maximum. The model magnetopause beyond this position is a cylinder attached to the edge of the ellipsoid at this location. This choice of shapes makes it easier to compare our results with earlier work which fit ellipsoids to (only) crossing data. In one of our two models, the focus of the ellipsoid lies at the center of the Earth, whereas in the other it lies at a position determined from fits to the data. We use a statistical criterion (called AIC) that lets us objectively determine which model better fits the data. As a result, we find that a model with an off-center focus better expresses the nature of the observed data. Despite differing mathematical formulations, our model results generally resemble those of Petrinec and Russell [1996]. Consequently, the mathematical expression is not the major reason why these models flare more (less) than the model of Roelof and Sibeck [1993] for very small (large) solar wind dynamic pressure.

AB - In this paper we unify two approaches to determining magnetopause shape and location from observations by fitting one model simultaneously to both the crossing data and the calculated data of magnetopause flaring angle, to achieve more accurate magnetopause shapes. We prepare two magnetopause models, each of which is an ellipsoid from the subsolar point to the position where the distance of the ellipsoid from the X axis is maximum. The model magnetopause beyond this position is a cylinder attached to the edge of the ellipsoid at this location. This choice of shapes makes it easier to compare our results with earlier work which fit ellipsoids to (only) crossing data. In one of our two models, the focus of the ellipsoid lies at the center of the Earth, whereas in the other it lies at a position determined from fits to the data. We use a statistical criterion (called AIC) that lets us objectively determine which model better fits the data. As a result, we find that a model with an off-center focus better expresses the nature of the observed data. Despite differing mathematical formulations, our model results generally resemble those of Petrinec and Russell [1996]. Consequently, the mathematical expression is not the major reason why these models flare more (less) than the model of Roelof and Sibeck [1993] for very small (large) solar wind dynamic pressure.

UR - http://www.scopus.com/inward/record.url?scp=0000656444&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0000656444&partnerID=8YFLogxK

M3 - Article

AN - SCOPUS:0000656444

VL - 104

SP - 247

EP - 261

JO - Journal of Geophysical Research

JF - Journal of Geophysical Research

SN - 0148-0227

IS - A1

M1 - 98JA02479

ER -