Peculiarities of the non‐adiabatic ion acceleration in the current sheet of the Earth magnetotail

Solar wind and ionospheric ions gain significant energy in the course of their interaction with magnetotail current sheet. The driver of this energization is the dawn‐dusk electric field but the acquired energy could be converted either to thermal energy (if ions are chaotically scattered) or to the kinetic energy of highly accelerated ion beams (∼1000–2500 km/s) moving in the vicinity of separatrix layer between open and closed magnetic field lines. This coherent mode of non‐adiabatic particle acceleration has some interesting peculiarities: mean energies of accelerated ion filaments obey the universal scaling law almost independent of magnetic field model and initial particle distribution function. Kinetic energy WN of each accelerated PSBL structures scales in dependence on its consecutive number: WN∼N4/3. This analytically obtained universal law conforms very well with the experimental data from Cluster spacecraft and results of numerical simulation.