- Abstract Breakdown of adiabaticity of the particle motion in the presence of the electric field perpendicular to the magnetic field may happen when the spatial scales of inhomogeneity is sufficiently larger than the electron gyroradius. This effect can provide non-adiabatic particle heating. Analysis of the electron trajectories in the inhomogeneous perpendicular electric field shows that the most important effect of this field is related to the change of the characteristic frequency of the periodic motion of particles. It is shown that the threshold effect of the local instability of the particles trajectories does not provide alone any special change of the electron temperature. However, the change of the frequency of particles rotation and the significant growth of the effective gyroradius can result in the non-adiabatic electron heating.