Speaker
Prof.
Mats André
(Swedish Institute of Space Physics, Uppsala)
Description
Magnetospheric ions with energies less than tens of eV originate from the
ionosphere. The low energy indicates the origin of the plasma but also severely
complicates detection of the positive ions onboard sunlit spacecraft at higher
altitudes, which often become positively charged to several tens of volts. We discuss
some methods to observe low-energy ions, including a recently developed technique
based on the detection of the wake behind a charged spacecraft in a supersonic flow.
We find that low-energy ions are common just inside the magnetopause.
During magnetopause magnetic reconnection events, these low-energy ions remain
magnetized down to smaller length-scales than the hot (keV) ions, introducing a new
scale. The Hall currents, carried by electrons, will be partially cancelled by magnetized
low-energy ions. We use observations by the Cluster spacecraft at the Earth’s
magnetopause to verify that when a mixture of ions of very different temperatures is
present in reconnecting plasmas, the microphysics related to the Hall effect is
significantly modified.
Primary author
Prof.
Mats André
(Swedish Institute of Space Physics, Uppsala)
Co-authors
Dr
Andris Vaivads
(Swedish Institute of Space Physics, Uppsala)
Dr
Sergio Toledo-Redondo
(Swedish Institute of Space Physics, Uppsala)
Dr
Yuri Khotyaintsev
(Swedish Institute of Space Physics, Uppsala)
