Ion Heating and Acceleration by Strong Magnetosonic Waves

Abstract

Large-amplitude magnetosonic waves ($\overrightarrow{\mathrm{k}}\perp \overrightarrow{\mathrm{B}}$) with ${\omega }_{\mathrm{ci}}<\omega <{\omega }_{\mathrm{lh}}$ (${\omega }_{\mathrm{ci}}$ and ${\omega }_{\mathrm{lh}}$ are the ioncyclotron and lower-hybrid frequencies) are investigated by particle simulation. Some ions are accelerated and trapped in the potential troughs of the waves; the $\overrightarrow{\mathrm{v}}\times \frac{\overrightarrow{\mathrm{B}}}{c}$ force accelerates these particles parallel to the phase fronts. Ultimately, the $\overrightarrow{\mathrm{v}}\times \frac{\overrightarrow{\mathrm{B}}}{c}$ force detraps the ions but only when $\overrightarrow{\mathrm{v}}$ is much larger than the Alfvén velocity; the wave is strongly damped by this effect.