Screened Coulomb potential in a flowing magnetized plasma

Abstract

Abstract. The electrostatic potential of a moving dust grain in a complex plasma with magnetized ions is computed using linear response theory, thereby extending our previous work for unmagnetized plasmas [P. Ludwig et al., New J. Phys. 14, 053016 (2012)]. In addition to the magnetic field, our approach accounts for a finite ion temperature as well as ion-neutral collisions. Our recently introduced code Kielstream is used for an efficient calculation of the dust potential. Increasing the magnetization of the ions, we find that the shape of the potential crucially depends on the Mach number M . In the regime of subsonic ion flow (M < 1), a strong magnetization gives rise to a potential distribution that is qualitatively different from the unmagnetized limit, while for M > 1 the magnetic field effectively suppresses the plasma wakefield.

Streaming Complex Plasmas: Ion Susceptibility for a Partially Ionized Plasma in Parallel Electric and Magnetic Fields

“…(15) is very slow for η = k 2 ⊥ r 2 L 1, i.e., when the perpendicular wavelength is much smaller than the Larmor radius, see Ref. [18]. However, there exists an alternative representation of the susceptibility, where the summation can be performed analytically, and the computation of χ i reduces to the evaluation of two integrals, see also Ref.…”

“…Crystalline and strongly coupled fluid states [15,16] also occur naturally in dusty plasmas due to the strong Coulomb interaction between the grains. Even though the dust particles themselves are difficult to magnetize [17], their screened interaction, and thus, their collective behavior, can be affected significantly by an external magnetic field [18].Dusty plasma experiments are often confronted with ion flows due to electric fields, especially in the sheath region. They affect the charging of the dust grains [19], their mutual interaction due to the formation of wake potentials [20,21], and give rise to drag forces [22,23].…”

“…It accounts for the non-Maxwellian velocity distribution and is applicable in a wide range of ion magnetization. Possible applications include the screening of a dust particle in the presence of streaming magnetized ions [18], the ion-dust streaming instability [37,38], and other phenomena, where flowing ions interact with charged microparticles in a strong external magnetic field. …”

“…Crystalline and strongly coupled fluid states [15,16] also occur naturally in dusty plasmas due to the strong Coulomb interaction between the grains. Even though the dust particles themselves are difficult to magnetize [17], their screened interaction, and thus, their collective behavior, can be affected significantly by an external magnetic field [18].…”

“…Various phenomena related to the interaction between ions and dust particles have been shown to be crucially affected by the different distribution, e.g., the ion-drag force [22,23] or the ion-dust streaming instability [24]. The ion susceptibility is the basis for several ion-dust related linear response calculations, including the screened dust potential [18,25,26]. In particular, the susceptibility is well known for ions in an external homogeneous electric field [22,27].…”