Note on the charging and spinning of dust particles in complex plasmas in a strong magnetic field

TLDR

The study examines how strong magnetic fields affect complex dusty plasmas, noting that dust grains can possess intrinsic magnetic moments and that only the extreme cases of strong electron and ion magnetization are considered. The authors estimate the magnetic moment arising from the balance between angular momentum transfer by plasma flux and neutral friction. The analysis shows that dust shape asymmetry and charging flux generate angular momentum that spins grains, with estimated rotation rates matching observations; magnetic moments interact weakly compared to Coulomb forces, producing an average magnetization, and increasing magnetic field first reduces then increases dust charge as electrons and ions become magnetized.

Abstract

Qualitative analysis of two new effects related to the influence of a strong magnetic field on the state of complex dusty plasmas is given. First, it is shown that the dust shape asymmetry, together with the presence of plasma charging flux, creates an angular momentum flux on a dust grain causing its rotation. The value of the estimated angular velocity is compared with that already observed. The magnetic moment related to the balance of the angular momenta transfer by plasma flux and the friction on neutrals is estimated. It is estimated that the interactions of these magnetic moments are usually much weaker than the Coulomb interactions. Apart from the magnetic moments induced by plasma flux the dust grain can have an intrinsic magnetic moment. Both of them create an average magnetization in complex plasmas. Second, it is shown that an increase in an external magnetic field first decreases the dust charges (when the electrons in the charging process start to be magnetized) and then, with a further increase of the magnetic field, the dust charges increase (when the ions in the charging process start to be magnetized). Only the limiting cases of strong electron and ion magnetization are discussed.