LESIA - Observatoire de Paris

Kinetic-scale plasma wave packet measured with the Fast Plasma Investigation on MMS

lundi 10 octobre 2016, par Adolfo F. Viñas (NASA Goddard Space Flight Center, Geospace Physics Laboratory, Greenbelt MD, USA)

Vendredi 21 octobre 2016 à 11h00 , Lieu : Salle de conférence du bâtiment 17

Kinetic-scale plasma wave packet resolved with the Fast Plasma Investigation on MMS The Fast Plasma Investigation on the Magnetospheric Multiscale mission provides two orders of magnitude higher time resolution than previous magnetospheric missions. Fast measurements from a constellation of four closely spaced observatories enable unprecedented investigations of kinetic-scale plasma physics. We present observations taken in the first year of MMS operation of structures with spatial scales below the thermal ion gyroradius. We analyze a kinetic Alfven wave packet in a reconnection jet near Earth’s dayside magnetopause. Multi-spacecraft particle and fields measurements are used to demonstrate that this packet travels obliquely to the magnetic field away from the magnetic reconnection site, and that energy is being transferred from the wave into the plasma. Further examination of the electron velocity distribution in the wave results in the discovery of a population trapped by the magnetic mirror force. This population accounts for 50% of the density variation in the wave packet and may lead to the generation of secondary instabilities. Implications for the future THOR mission will be discussed.