Cold-Ion Populations and Cold-Electron Populations in the Earth’s Magnetosphere and Their Impact on the System

Cold-ion populations and cold-electron populations are extremely difficult to measure in the Earth’s magnetosphere, and their properties, evolutions, and controlling factors are poorly understood. They are sometimes referred to as the “hidden populations”. But they are known to have multiple impacts on the behavior of the global magnetospheric system. These impacts include (a) the reduction of the dayside reconnection rate and consequently the reduction of solar-wind/magnetosphere coupling, (b) alteration of the growth rate and saturation amplitudes of plasma waves resulting in alterations of the energization rates of the radiation belts, (c) changes in plasma-wave properties resulting in changes in the loss rates of the ring current and radiation belts, (d) changes in the mass density of the magnetosphere resulting in changes in the radial diffusion of the radiation belts, (e) spatial and temporal structuring of the aurora, (f) altering magnetotail reconnection, (g) changing spacecraft charging, and (h) acting as sources for warm and hot magnetospheric populations.

A recent workshop on the cold-particle populations of the magnetosphere inspired new work on the outstanding problems caused by a lack of understanding of those cold populations. This Research Topic will collect reports of that new work and will stimulate the formation of author teams to write review articles on what is known and what needs to be known. Commentaries assessing the present situation and guiding the research field into the future will be solicited from the community. Methods articles describing new measurement techniques and new spaceflight mission concepts will be welcomed.

This Research Topic will look for original-research papers, commentaries, and review articles focusing on (1) statistical surveys of existing data sets to obtain information about the properties, evolution, and controlling factors for the cold-ion and cold-electron populations of the magnetosphere; (2) evidence that will uncover the sources of the various cold-ion and cold-electron populations of the magnetosphere; (3) theoretical calculations, computer simulations, and data-analysis studies of the impacts of the cold-ion and cold-electron impacts on the global magnetospheric system; (4) measurement concepts for future space-flight instrumentation that can measure the properties of the cold ions and cold electrons of the magnetosphere; and (5) new mission concepts focusing on science that would be enabled by measurements of cold ions and cold electrons. Authors wishing to submit reviews or mini-reviews might coordinate their topics with the Guest Editors.