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Abstract:

Strong energization of ions across the background magnetic field is one of most interesting observations in the solar corona at 1 5-4 solar radii and in the auroral zones of the terrestrial magnetosphere at 1 5-4 Earth radii The commonly accepted interpretation of this phenomenon is based on the ion-cyclotron resonant heating by high-frequency waves in the solar corona or stochastic heating by small-scale waves in the auroral zones We propose another mechanism where the cross-field ion energization is due to non-adiabatic acceleration by low-frequency kinetic Alfven waves KAWs In the vicinity of even demagnetizing wave phases all ions undergo a simultaneous increase of their cross-field velocities similar to particle acceleration in quasi-perpendicular shocks It is therefore intuitively understandable why the particles that move against the waves enter the regime of acceleration easier In-situ measurements of electro-magnetic fields in the auroral zones and remote spectroscopic coronal observations are compatible with low-frequency KAW turbulence We demonstrate that the sporadic appearance of super-critical gradients in KAW turbulence is sufficient for the cross-field energization of ions observed in these regions.