particle acceleration processes, and their consequences for electromagnetic radiation and energy transport in highly magnetised plasmas



Auroral Science with Alfvén

The primary objective of the Alfvén mission is to understand the physical processes that enable electromagnetic energy to be converted to charged particle kinetic energy in a low beta plasma, using the Earth´s auroral acceleration region (AAR) as an exemplar.

These poorly understood fundamental plasma physical processes play a central role in the electrical current systems that control the dynamics of the magnetosphere, and deposit significant amounts of energy in the Earth´s thermosphere and ionosphere.

Energy conversion must happen where magnetic field aligned currents are accompanied by magnetic field aligned electric fields.

Previous missions have discovered large scale quasi-static parallel electric fields in the AAR, but it is currently unknown how they are created and maintained.

Similarly, earlier missions suggest that Alfvén waves must transmit their energy to auroral electrons, but it is unknown where and how this second conversion mechanism operates.

To answer these fundamental, long-standing questions in a system-science approach, simultaneous coordinated measurements of electric potentials and energy flux from two spacecraft in the AAR region are required, along with auroral imaging for context.

This has not previously been possible, but is now compelling and timely.

The mission will also contribute unique observations of radiation belt precipitation losses, inportant for the science of the radiation belts and the upper atmosphere.


Andrew Fazakerley and Matthieu Berthomier


Alfvén M4 - Last Updated 02 April 2015

Auroral photograph courtesy NASA.