Negative ion-drag force in a plasma of gas discharge

The Monte Carlo simulation technique was employed to calculate the ion-drag force (IDF) under the experimental conditions of a radio frequency gas discharge bulk plasma. We found a new regime in which the IDF is negative. It is essential that the ion collisions with the gas atoms are taken into account. A phase diagram, depending on the gas pressure and the Debye screening length, was constructed indicating the sign of the IDF.