ESA Science & Technology - Effect on Earth's magnetosphere of the CME of 20 January 2005

This simulation depicts the effect of the aftermath of a coronal mass ejection (CME) on the plasma density of the Earth's magnetosphere. It covers the period 18:00 UT on 21 January 2005 to 06:00 UT on 22 January 2005.

This particular CME occurred on 20 January 2005 and was later shown to be one of the fastest CMEs during solar cycle 23. As a result, it took only 34 hours for the cloud of plasma to cross the 150 million km gulf between the Sun and Earth, compared with the typical time of 3-4 days. A consequence of this was that the fast-moving cloud acted like a snow plough, driving into slower-moving solar wind material ahead of it and compressing the plasma so that it piled up in a high density - high temperature sheath region, preceded by an interplanetary shock.

In this simulation plasma density is colour-coded, with red representing the highest density; orange, yellow and green representing progressively lower density; and dark blue depicting the lowest density. The location of Earth is indicated and the Sun is (out of frame) to the right. The magnetosheath is shown as a red/orange band on the Sun side of the magnetosphere and extending along the flanks.

At the start of the simulation, the solar wind is moderately dense (yellow). The arrival of the solar filament from the Sun side is clearly seen by the increase in plasma density (orange). As it engulfs and compresses the magnetosphere, the magnetosheath increases in density (orange/red).

A short while later the peak densities in the solar filament arrive (dark orange) and about one hour later the densities in the magnetotail are seen to increase (represented by the colour change from blue to green to yellow) filling from the flanks inward to the centre.

The filament density starts to drop (yellow/green) upstream of Earth as its trailing edge passes by, and the plasma sheet returns to a hot, low density state (blue).

This simulation of plasma density in the magnetosphere on 21-22 January 2005 was made using the University of Michigan's Space Weather Modeling Framework and is provided for community use through Goddard Space Flight Center's Community Coordinated Modeling Center. The view is looking downward from above the equatorial plane. At the start of the simulation the interplanetary magnetic field (IMF) is southward, during the period of the high magnetospheric densities it is northward, and it then turns intermittently southward as the densities drop by the end of the simulation.

Further details of this solar event can be found in Solar filament impact on 21 January 2005: Geospace consequences, by J.U. Kozyra and colleagues.

Credit: Visualisation by Lutz Rastaetter, Community Coordinated Modeling Center/NASA Goddard Space Flight Center