Measurements of the dust-ion momentum transfer frequency and ion drag force in complex plasmas

• A simple self-consistent method to estimate the effect of the streaming ions on microparticles in a positive column of a dc discharge plasma is presented. The momentum transfer frequency in dust-ion collisions and the ion drag force are determined within a wide range of gas pressures, p = 20 - 120 Pa. The method does not require a priory knowledge of the particle charge, but involves only the particle charge gradient which is recovered from the same experimental data. The method depends only on two experimental quantities: dust particle drift velocity and electric field, thus minimizing the errors in the estimates. Reasonable agreement is found between our force measurements and theoretical predictions, corresponding to the regime of moderate ion-dust particle coupling.

Nyckelord

complex plasma

ion drag force

momentum transfer frequency

flow

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