workshop on Cold plasma of ionospheric origin:

implications for magnetospheric dynamics

2 - 4 July 2018, ESAC/ESA, Madrid (Spain)

 

Cold ions and electrons of ionospheric origin are known to escape from the ionosphere and populate most regions of the magnetosphere. Together with the solar wind, they are the main source of magnetospheric plasma, and there are a large number of studies addressing their occurrence and variability.

It has been found that cold ions are often composed by a mixture of H+, He+ and O+, their spatial distribution is patchy and irregular, and are statistically shifted towards the dusk side. Past studies have also demonstrated that the cold ions are important to the global dynamics of the Earth’s magnetosphere. They constitute a non-negligible fraction of the magnetospheric plasma density in the outer magnetosphere, where magnetic reconnection with the solar wind takes place, modifying the coupling between these two plasma regions. Moreover, ionospheric outflows are an important source of cold plasma in the Earth's magnetotail, where magnetic reconnection also occurs and large amounts of energy stored by magnetic fields are converted into kinetic energy of the particles.

Recently, the Magnetospheric MultiScale (MMS) mission, launched by NASA in 2015, has resolved the smallest scales of magnetospheric plasmas for the first time, including cold ion and electron length scales, which are smaller than hot ion length-scales owing to their smaller gyroradius. There are detailed observations both at the dayside magnetopause and magnetotail of the cold plasma component interacting via magnetic reconnection with the magnetospheric plasma. An increasing number of studies of the microphysics that the cold ions introduce, often supported by state-of-the-art numerical simulations, is becoming available. On the other hand, the effect of cold electrons remains largely unexplored up to date.

The aim of this team is to first compile the knowledge from more than 50 years of cold plasma observations in the magnetosphere, including more recent global models which have included part of the data, with the purpose of setting the direction of the future studies related to the cold plasma component in the magnetosphere. These new studies can account for the plasma microphysics that cold ions and electrons introduce owing to the high-resolution observations and numerical simulations available nowadays.