Charged Particle Motion in Earth's Magnetosphere

Precipitation of Magnetospheric Charged Particles

Magnetospheric charged particles on closed magnetic field lines (both ends of which penetrate the earth’s atmosphere) find themselves in a magnetic mirror geometry. Unless they are traveling nearly parallel to the magnetic field, they bounce back and forth between the Northern and Southern Hemispheres on paths high above the dense regions of the earth’s upper atmosphere.

Animation courtesy the COMET and HAO programs at UCAR/NCAR.

If, however, their paths are nearly parallel to the field lines, they can reach atmospheric regions where they collide with neutrals. By this process, charged particles precipitate from the magnetosphere into the atmosphere. The range of small pitch angles through which particles are precipitated is called the loss cone.

Pitch angles

As plasma sheet field lines approach the earth, the loss cone expands. In addition, charged particles can be scattered into the loss cone by magnetic and electrical disturbances in the magnetosphere. Particles precipitated via the loss cone from the magnetosphere into the upper atmosphere produce the aurora.

Animation courtesy the COMET and HAO programs at UCAR/NCAR.

Last modified May 17, 2005 by Randy Russell.

You might also be interested in:

Cool It! Game

Check out our online store - minerals, fossils, books, activities, jewelry, and household items!...more

Saturn's Aurora

Have you ever seen the Southern or Northern Lights? Did you know that Earth isn't the only planet that puts on these beautiful light shows, also known as the "aurora"? Auroral displays have also been observed...more

Earth's Magnetic Poles

Earth has a magnetic field. If you imagine a gigantic bar magnet inside of Earth, you'll have a pretty good idea what Earth's magnetic field is shaped like. Of course, Earth DOESN'T have a giant bar magnet...more

Earth's North Magnetic Pole

Earth has a global magnetic field that is approximately, though not exactly, a dipole field (like a bar magnet) with a north pole and a south pole. Earth's North Magnetic Pole (NMP) is not in the same...more

Charged Particle Motion in Earth's Magnetosphere

Motions within Earth's metallic core generate the planet's global magnetic field. This magnetic field extends beyond Earth's surface and atmosphere into the space surrounding our home planet. The interaction...more

Altocumulus

Altocumulus clouds (weather symbol - Ac), are made primarily of liquid water and have a thickness of 1 km. They are part of the Middle Cloud group (2000-7000m up). They are grayish-white with one part...more

Altostratus

Altostratus clouds (weather symbol - As) consist of water and some ice crystals. They belong to the Middle Cloud group (2000-7000m up). An altostratus cloud usually covers the whole sky and has a gray...more

Cirrocumulus

Cirrocumulus clouds (weather symbol - Cc) are composed primarily of ice crystals and belong to the High Cloud group (5000-13000m). They are small rounded puffs that usually appear in long rows. Cirrocumulus...more

Windows to the Universe, a project of the National Earth Science Teachers Association, is sponsored in part is sponsored in part through grants from federal agencies (NASA and NOAA), and partnerships with affiliated organizations, including the American Geophysical Union, the Howard Hughes Medical Institute, the Earth System Information Partnership, the American Meteorological Society, the National Center for Science Education, and TERC. The American Geophysical Union and the American Geosciences Institute are Windows to the Universe Founding Partners. NESTA welcomes new Institutional Affiliates in support of our ongoing programs, as well as collaborations on new projects. Contact NESTA for more information. NASA ESIP NCSE HHMI AGU AGI AMS NOAA