  We study theoretically a dynamics of $\varphi_0$ junction with direct
coupling between magnetic moment and Josephson current which shows features
close to Kapitza pendulum. We have found that starting with oscillations along
$z$-axis, the character of magnetization dynamics changes crucially and stable
position of magnetic moment $\vec m$ is realized between $z-$ and $y$-axes
depending on parameters of the system. Changes in critical current and
spin-orbit interaction lead to the different stability regions for
magnetization. An excellent agreement between analytical and numerical results
is obtained for low values of the Josephson to magnetic energy ratio.

Superconductivity