Low-Frequency Ion Oscillations during the Expansion of Ultracold Plasma

The results of calculations using the molecular dynamics method of low-frequency ion oscillations in ultracold plasma, previously observed in the experiment, are presented. Oscillations of the radial velocity of ions and changes in the direction of their flows during the expansion of ultracold plasma in a quadrupole magnetic field are detected. This is due to the influence of the magnetic field on the charge imbalance, which leads to the simultaneous existence of potential wells for both electrons and ions. Ion temperature oscillations with a frequency close to the ion plasma frequency are also detected. Satisfactory agreement with the experiment is obtained.