Magnetosphere Introduction


ECE120 Space Physics.

Interplanetary space appears dark and empty and until recent discoveries made at the beginning of the space program in 1958, it was thought to be relatively empty and stable.

The space surrounding the earth was found to be filled with magenetic fields, electric fields, matter, energy and a constantly changing and dynamic form of turbulent space weather. Involving interactive magnetic fields and flowing plasmas.

Figure 1 Figure 1.

Space weather originates on the sun and flows toward the earth at supersonic speed in the form of plasma. This high speed, hot, collisionless plasma drags along with it the magnetic field of the sun. The solar wind reaches the earth in 2 or 3 days then continues on out into the solar system.

It has been known for centuries that the earth has a magnetic field. The earths magnetic field is similar to a large dipole magnet that is closely, but not exactly, aligned to the rotational axis of the earth.

Figure 2
Figure 2.

The solar plasma carries a large amount of energy and interacts with the earths magnetic field causing many dynamic processes on and around the earth.

Only some of the magnetic effects observed on the earth come from the magnetosphere. The only visual effects are the polar auroras that are mostly seen at higher latitudes toward the poles.(Aurora Borealis, Aurora Australis) Fluctuations of the near earth magnetic field can also be detected and are a result of magnetic storms and sub-storms that come from sudden magnetic field changes in space.

Even though the interactive effects of the solar wind on the earth's magnetic field are not immediately noticable, the long term effects on physical processes such as climate, weather and other atmospheric conditions is significant. The continued study of the solar wind and earths magnetosphere will help in forecasting future events that will effect the solar-terrestrial environment of the earth.

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