Multi-spacecraft investigation of the auroral acceleration region using Cluster

 
 

The Cluster mission is the first multi-spacecraft mission to explore Earth’s magnetosphere plasma environment with four spacecraft flying in close formation. Launched in 2000, these spacecraft have provided valuable new insights into a range of magnetospheric phenomena and space plasma physics. Although originally in a 4x19 RE orbit, the spacecraft perigee has dropped such that since 2008 the spacecraft have been regularly passing over the auroral regions at altitudes as low as a few thousand kilometres. It is at these altitudes that magnetospheric particles are accelerated along the magnetic field into the ionosphere, in violation of ideal magnetohydrodynamics. The collisions between these energised particles and the cold ionospheric particles creates the aurora.


This team brings together experts on the auroral acceleration processes and multi-spacecraft studies of space plasmas in order to exploit this exciting new dataset in space plasma physics. We will attempt to address questions such as:


  1. What is the in-situ analogue of narrow-band fine structure in auroral radio emission (auroral kilometric radiation-AKR)?

  2. What is the electric potential structure of the auroral acceleration region (AAR) and how does it vary?

  3. How do charged particle distributions vary along the AAR?

  4. How does the structure in the AAR vary in space?


These questions will initially be addressed by a number of case studies of optimum events identified in the data.

Top: Aurora Australis photographed from the ISS (courtesy NASA)


Bottom: Artists impression of the Cluster spacecraft (courtesy ESA)