Image Title: Ring Particles Pushed by Magnetic Forces Target Name: J Rings Is a satellite of: Jupiter Mission: Galileo Spacecraft: Galileo Orbiter Instrument: Solid State Imaging Produced By: Cornell University Creation Date: 1998-09-15 Primary Data Set: Galileo EDRs Full-Res JPEG: R18_magforce2_full.jpg (178 kbytes)

Original Caption Released with Image:

This artist's sketch illustrates that the magnetic force on a charged ring grain partly pushes particles out of the ring plane and that the strength and direction of this out-of-plane force depends both on where the particle is in the ring plane as well as on Jupiter's rotational orientation. In these figures, Jupiter's spin axis is vertical; however, Jupiter's dipolar magnetic field (dotted lines) is tilted about 10 degrees from the planet's spin axis. Thus, the magnetic field is not perfectly vertical when it passes through the ring plane in which the ring particles are orbiting. (The magnetic field lines are represented by the yellow dotted lines; the yellow arrows indicate the direction of the field.) The magnetic forces (red arrows) on a ring particle are simultaneously perpendicular to the particle's direction of motion (in the ring plane) and to the magnetic field lines (yellow dotted lines). The magnetic force on a negatively charged ring particle points mainly outward from the planet. With Jupiter oriented as shown in the top panel, the magnetic forces have a slightly downward force on particles at the right of Jupiter and a slightly upward force on particles at the left of Jupiter.

The bottom panel shows Jupiter five hours later, after the planet has rotated 180 degrees, half a rotation. At this point the part of the magnetic force out of the equatorial plane reverses direction. Thus every charged ring grain experiences an oscillating vertical force. Some of these forces oscillate with periods that are multiples of the particles' orbital periods. Such synchronous periods lead to especially large, resonant (enhanced) effects.

The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC.

This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://www.jpl.nasa.gov/galileo. Background information and educational context for the images can be found at: http://www.jpl.nasa.gov/galileo/sepo.

Image Note:

Related Release

Artist's drawing by Jim Houghton.

This page is not a Planetary PhotoJournal release, but is an illustration provided by the Galileo imaging (SSI) team as further background for other releases of imaging data.

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Galileo Solid State Imaging Team Leader: Dr. Michael J. S. Belton

The SSI Education and Public Outreach webpages were originally created and managed by Matthew Fishburn and Elizabeth Alvarez with significant assistance from Kelly Bender, Ross Beyer, Detrick Branston, Stephanie Lyons, Eileen Ryan, and Nalin Samarasinha.

Last updated: September 17, 1999, by Matthew Fishburn

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