Abstract
The behavior of the energy loss function (ELF) for fast electrons in ionospheric plasma is investigated over a wide energy range. It is demonstrated that at high energies (greater than 2 eV), the results obtained using the widely used Swartz approximation for calculating energy losses deviate significantly from the values obtained using the quantum approach proposed by Larkin. Using the kinetic approach, a universal expression for calculating losses over a wide energy range is derived. This expression yields results that agree well with those obtained using the Swartz approximation for low energies (less than 2 eV) and those calculated taking quantum effects into account using Larkin’s approach.