Like Earth, Saturn has an invisible ring of energetic ions trapped in its
magnetic field. This feature is known as a "ring current." This ring
current has been imaged with a special camera on Cassini sensitive to
energetic neutral atoms.
This is a false color map of the intensity of the energetic neutral atoms
emitted from the ring current through a processed called charged exchange.
In this process a trapped energetic ion steals and electron from cold gas
atoms and becomes neutral and escapes the magnetic field.
The Cassini Magnetospheric Imaging Instrument's ion and neutral camera
records the intensity of the escaping particles, which provides a map of
the ring current. In this image, the colors represent the intensity of
the neutral emission, which is a reflection of the trapped ions. This
"ring" is much farther from Saturn (roughly five times farther) than
Saturn's famous icy rings. Red in the image represents the higher
intensity of the particles, while blue is less intense.
Like Earth, Saturn has an invisible ring of energetic ions trapped in its
magnetic field. This feature is known as a "ring current." This ring
current has been imaged with a special camera on Cassini sensitive to
energetic neutral atoms.
This is a false color map of the intensity of the energetic neutral atoms
emitted from the ring current through a processed called charged exchange.
In this process a trapped energetic ion steals and electron from cold gas
atoms and becomes neutral and escapes the magnetic field.
The Cassini Magnetospheric Imaging Instrument's ion and neutral camera
records the intensity of the escaping particles, which provides a map of
the ring current. In this image, the colors represent the intensity of the
neutral emission, which is a reflection of the trapped ions. This "ring"
is much farther from Saturn (roughly five times farther) then Saturn's
famous icy rings. Red in the image represents the higher intensity of the
particles, while blue is less intense.
Saturn's ring current had not been mapped before on a global scale, only
"snippets" or areas were mapped previously but not in this detail. This
instrument allows scientists to produce movies (see PIA10083) that show how this
ring changes over time. These movies reveal a dynamic system, which is
usually not as uniform as depicted in this image. The ring current is
doughnut shaped but in some instances it appears as if someone took a bite
out of it.
This image was obtained on March 19, 2007, at a latitude of about 54.5
degrees and radial distance 1.5 million kilometres (920,000 miles). Saturn
is at the center, and the dotted circles represent the orbits of the
moon's Rhea and Titan. The Z axis points parallel to Saturn's spin axis,
the X axis points roughly sunward in the sun-spin axis plane, and the Y
axis completes the system, pointing roughly toward dusk. The ion and
neutral camera's field of view is marked by the white line and accounts
for the cut-off of the image on the left. The image is an average of the
activity over a (roughly) 3-hour period.
For more information about the Cassini-Huygens mission, visit
http://saturn.jpl.nasa.gov/home/index.cfm and the instrument
team's home page, http://sd-www.jhuapl.edu/CASSINI/index.html.