Magnetic reconnection is a process that converts magnetic energy into kinetic energy, both bulk and thermal. We study the energy partition in magnetotail reconnection in the presence of cold ion populations of ionospheric origin using kinetic simulations. We compare two simulations with one or two ion populations, but same ion moments. The ion distribution in the simulation with cold ions therefore corresponds to a non‐Maxwellian distribution with a large tail. The global energy budget does not change in the two cases, but when focusing on sub‐populations, the hot ion population (i.e., the tail of the velocity distribution function) gains more energy than the cold ion population (i.e., the core of the distribution). Hot and cold ions also gain different percentages of bulk and thermal energy.
N2 - Plain Language Summary: Magnetic reconnection is a process that converts magnetic energy into acceleration (bulk kinetic energy) and heating (thermal kinetic energy). In the magnetosphere, we often see a cold plasma population of ionospheric origin, on top of the hot magnetospheric plasma. We study the energy partition in magnetotail reconnection in the presence of those cold ions using simulations. We compare two simulations with and without cold ions, but same global parameters. We observe that the total energy partition is not significantly different between the simulations. But when focusing on the cold ion simulation, we see that hot ions gains more energy than cold ions and also have a larger bulk over thermal energy gain. N2 - Key Points:The energy budget in magnetic reconnection is not significantly affected by cold ion beams for constant inflow plasma global parameters
The hotter ion population gains more energy during magnetic reconnection than the colder one
Most of the energy gain of hot ions is in the form of internal energy, while the energy transferred to the cold ions is more balanced