Current Systems

Currents in a magnetosphere are like arteries in the human body. They are the manifestation of particles being carried from one region to another. Moreover, they are an integral part of what creates the magnetosphere itself.

The presence of magnetic fields leads to the existence of currents, and the presence of currents leads to magnetic fields. The two are intricately intertwined. Thus in a planetary magnetosphere, the bending and twisting magnetic fields lead to a dist inct set of current systems.

There are three main current systems in a magnetosphere.

  • Chapman-Ferraro currents (in green)
  • cross-tail currents (in blue)
  • Field-Aligned currents (FAC's) in red)

The Chapman-Ferraro currents enclose and confine the global magnetosphere. They are found in the vicinity of the magnetopause.

Cross-tail currents pass through the center of the magnetotail, and cause that region to be known as the "current sheet".

Field-Aligned currents are transient currents which short-circuit through a planets ionosphere (which is a conducting medium), and which are part of generating the aurora.

Return to "What is a Magnetosphere?"

You might also be interested in:

Traveling Nitrogen Classroom Activity Kit

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

Magnetosphere

A magnetosphere has many parts, such as the bow shock, magnetosheath, magnetotail, plasmasheet, lobes, plasmasphere, radiation belts and many electric currents. It is composed of charged particles and...more

The forming Aurora

This picture illustrates the streaming of particles into and out of the auroral zone, as Field-aligned currents (FAC's) short-circuit through the ionosphere. Some of the particles entering the auroral...more

The Plasma Sheet

The plasma sheet is simply that, a sheet of plasma that extends down the magnetotail dividing the two lobes of the Earth's magnetic field. The particle density here is about 0.5 cm-3 for both electrons...more

Torus

A satellite which has an atmosphere, such as Jupiter's moon Io, will leave a cloud of particles behind as it orbits the planet. Rhea, a body with an icy surface exposed to energetic particles, will have...more

Space Weather throughout the Solar System

The Sun is surrounded by a "bubble" in space called the heliosphere. In a sense, we Earthlings live within the outer atmosphere of our Sun. The solar wind fills the heliosphere with energetic...more

AU

AU stands for Astronomical Units. Distances in space are too large to measure in Earth standards like miles or kilometers. For distances too large to measue in AU, we use light years. A light year is the...more

The Spiral of the IMF

The solar wind is formed as the Sun's topmost layer blows off into space carrying with it magnetic fields still attached to the Sun. Gusts and disturbances form in the solar wind associated with violent...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