FORECAST SOL: Moderate yellow MAG: Normal green ION: Normal green
HomeSatelliteSatellite EnvironmentMagnetopause Model Monday, May 27 2024 10:25 UT
Satellite Environment

Magnetopause model

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Geostationary satellites are usually protected to some extent from the effects of solar energetic particles by the Earth's magnetic field. But, when the magnetopause, the abrupt boundary separating the solar wind from the Earth's magnetic field, is pushed towards Earth (inside GEO orbits) by a major coronal mass ejection, some satellites will lose this protection and suffer damage from an increased flux of high energy particles.

Damage of this sort is sometimes severe. Take for example the Equator-S mission:

Unfortunately, the mission was damaged by several malfunctions. On 17 December 1997 the primary master processor unit failed, and on 30 April 1998 the second unit experienced the same problem. This caused the premature end of the mission. Failure analysis attributed both events to a latch-up in one the RAM-chips used by the processors. It is not unlikely that deep dielectric charging by the high energetic electron fluxes in December 1997 as well as in April 1998 was the cause of the latch-ups.

This tool displays the estimated location of the Earth's magnetopause.


The stand-off distance and shape of the magnetopause are controlled by the dynamic and static pressure of the solar wind, the pressure of the Earth's magnetic field, and the orientation of the Interplanetary Magnetic Field (IMF). The solar wind and IMF field data used for this model originate from the NOAA/NASA DSCOVR (Deep Space Climate Observatory) spacecraft orbiting the L1 point (a point between the Sun and Earth where gravitational forces balance).

The graphical presentation is in the equatorial plane as viewed from above the Earth's north pole. Geosynchronous orbit is shown at a distance of 6.6 Earth radii (Re) from the centre of the planet, with four longitude spokes. The locations of several geosynchronous satellites are indicated, with the legend in the lower left identifying the satellites. All the satellites are actually at the same orbital radius, though the display adjusts these in some cases for clarity.


Shue JH et al, A new functional form to study the solar wind control of the magnetopause size and shape, JGR, v102, pp9497-9511, May 1997.

Shue JH et al, Magnetopause location under extreme solar wind condition, JGR, v103, pp17691-17700, August 1998.

G. Haerendel, R. B. Torbert, H. Höfner. Introduction: The Equator-S mission. Annales Geophysicae, European Geosciences Union, 1999, 17 (12), pp.1499-1502. hal-00316714

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