Saturn Hit By Strong Blast Of Solar Wind; Sheds Light On Cosmic Particle Accelerators

 

During a chance encounter with what appears to be an unusually strong blast of solar wind at Saturn, NASA’s Cassini spacecraft detected particles being accelerated to ultra-high energies. This is similar to the acceleration that takes place around distant supernovas.

Since we can’t travel out to the far-off stellar explosions right now, the shockwave that forms from the flow of solar wind around Saturn’s magnetic field provides a rare laboratory for scientists with the Cassini mission — a partnership involving NASA, the European Space Agency and the Italian Space Agency — to observe this phenomenon up-close. The findings, published this week in the journal Nature Physics, confirm that certain kinds of shocks can become considerably more effective electron accelerators than previously thought.

This illustration shows “quasi-parallel” (top) and “quasi-perpendicular” (bottom) magnetic field conditions at a planetary bow shock. Bow shocks are shockwaves created when the solar wind blows on a planet’s magnetic field. 

Under quasi-parallel conditions, the planet’s magnetic field is roughly pointing toward the shock surface, almost parallel to a vector at right angles to the shock front (red arrow). Under quasi-perpendicular conditions, the magnetic field is close to aligned with the shock surface, that is, almost perpendicular to the shock vector. 

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL manages the mission for NASA’s Science Mission Directorate, Washington. JPL is a division of the California Institute of Technology, Pasadena. 

Credits: ESA