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Entering the Plasmasphere - Windows to the Universe

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Become a nitrogen atom in the nitrogen cycle in our Traveling Nitrogen Classroom Activity Kit/Game. See all our games, activity kits and classroom activities.
This animation shows how particles from the Sun are diverted by the Earth's magnetic field.
Movie provided courtesy of Professor Patricia Reiff, Rice University Connections Program

How Does the Earth's Magnetic Field Protect Us From Space Radiation?

Dangerous particles are not able to penetrate to the Earth's surface but are forced by the magnetic field to move around the Earth. Particles gain entry through the cusps that are shaped like funnels over the polar regions or they gain entry far downstream from the Earth. The particles that enter downstream travel toward the Earth and are accelerated into the high-latitude ionosphere and produce the auroral oval light shows. Since the most intense auroras occur at solar maximum, it was once thought that the Sun hurled material out during these raised times of solar activity and that that material funneled directly into the polar cusps. However, we now understand that the electrons that cause the auroras come in downstream or from the Earth's magnetic tail. These electrons that enter at the magnetotail are energized locally within the magnetosphere.

Other higher energy particle radiation that could pose a danger to life here on Earth, is forced to drift around the Earth within two large donut-shaped regions called the radiation belts. Invisible magnetic fields are the reason that particle radiation moves in this way. Click here for basic facts about particle motions in the Earth's magnetic field.

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Radiation Belts

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Basic Facts About the Effects of Magnetic Fields on Charged Particles

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The Earth's Magnetosphere

The Earth has a magnetic field with north and south poles. The magnetic field of the Earth is enclosed in a region surrounding the Earth called the magnetosphere. As the Earth rotates, its hot core generates...more


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The Spiral of the IMF

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Spiral Path of Material

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The SAR Arc

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Windows to the Universe, a project of the National Earth Science Teachers Association, is sponsored in part by the National Science Foundation and NASA, our Founding Partners (the American Geophysical Union and American Geosciences Institute) as well as through Institutional, Contributing, and Affiliate Partners, individual memberships and generous donors. Thank you for your support! NASA AGU AGI NSF