skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Effective charge of a small absorbing body in highly collisional plasma subject to an external electric field

Abstract

The total force which is the resultant of the electric, ion, and electron drag forces has been calculated for a small absorbing spherical grain immersed in a highly collisional, weakly ionized plasma subject to a weak external electric field. Linear dielectric response formalism has been used and both ion and electron absorption on the grain have been taken into account. It is shown that the total force is always directed along the direction of the electric force. The 'effective' charge of the grain which can be defined as the ratio of the total force to the strength of the electric field is calculated. It is shown that its magnitude is comparable to the magnitude of the actual grain's charge.

Authors:
; ;  [1]
  1. Max-Planck Institut fuer Extraterrestrische Physik, D-85741 Garching (Germany)
Publication Date:
OSTI Identifier:
20976613
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 14; Journal Issue: 5; Other Information: DOI: 10.1063/1.2724806; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; ABSORPTION; COLLISIONAL PLASMA; COLLISIONS; DIELECTRIC MATERIALS; DIELECTRIC PROPERTIES; DRAG; EFFECTIVE CHARGE; ELECTRIC FIELDS; ELECTRONS; IONS; SPHERICAL CONFIGURATION

Citation Formats

Chaudhuri, M., Khrapak, S. A., and Morfill, G. E.. Effective charge of a small absorbing body in highly collisional plasma subject to an external electric field. United States: N. p., 2007. Web. doi:10.1063/1.2724806.
Chaudhuri, M., Khrapak, S. A., & Morfill, G. E.. Effective charge of a small absorbing body in highly collisional plasma subject to an external electric field. United States. doi:10.1063/1.2724806.
Chaudhuri, M., Khrapak, S. A., and Morfill, G. E.. Tue . "Effective charge of a small absorbing body in highly collisional plasma subject to an external electric field". United States. doi:10.1063/1.2724806.
@article{osti_20976613,
title = {Effective charge of a small absorbing body in highly collisional plasma subject to an external electric field},
author = {Chaudhuri, M. and Khrapak, S. A. and Morfill, G. E.},
abstractNote = {The total force which is the resultant of the electric, ion, and electron drag forces has been calculated for a small absorbing spherical grain immersed in a highly collisional, weakly ionized plasma subject to a weak external electric field. Linear dielectric response formalism has been used and both ion and electron absorption on the grain have been taken into account. It is shown that the total force is always directed along the direction of the electric force. The 'effective' charge of the grain which can be defined as the ratio of the total force to the strength of the electric field is calculated. It is shown that its magnitude is comparable to the magnitude of the actual grain's charge.},
doi = {10.1063/1.2724806},
journal = {Physics of Plasmas},
number = 5,
volume = 14,
place = {United States},
year = {Tue May 15 00:00:00 EDT 2007},
month = {Tue May 15 00:00:00 EDT 2007}
}
  • It is shown that the total frictional (drag) force acting on a slowly moving absorbing grain in a stationary weakly ionized high pressure plasma can be directed along its motion, causing the grain acceleration. At some velocity the forces associated with different plasma components balance each other, allowing free undamped superfluid motion of the grain.
  • An exact solution to the linearized problem of the behavior of a collisional plasma in a half-space in an external alternating electric field is obtained. Mirror boundary conditions are used. The eigenvectors of the corresponding characteristic system are found in the space of generalized functions, and the eigenvalue spectrum is investigated. A theorem on the expansion of the solution of the investigated boundary-value problem with respect to eigenvectors is proved. An expression for calculating a discrete mode is found explicitly.
  • The charging of a metal sphere in a weakly ionized collisional plasma in a uniform external electric field is investigated with allowance for the effect of the space charge field and ionization-recombination processes. The sphere charge and the spatial distributions of charged plasma particles are calculated both numerically and analytically (for some particular cases) for the case of a strong external field. It is found that the size of the perturbed plasma region is determined by the external field and the intensity of recombination processes. It is shown that the total electric charge (the sphere charge plus the plasma spacemore » charge) is zero in accordance with predictions of the theory of static currents in a conducting medium.« less
  • The theory of large-scale fluctuations in a plasma is used to calculate the correlations functions of electron and ion density with regard to particle collisions described within the Bhatnagar-Gross-Krook (BGK) model and the presence of a constant external electric field. The changes of plasma particle distribution functions due to an external electric field and their influence on the plasma dielectric response are taken into account. The dispersion relations for longitudinal waves in such a plasma are studied in details. It is shown that external electric field can lead to the ion-acoustic wave instability and anomalous growth of the fluctuation level.more » Detailed numerical studies of the general relations for electron number density fluctuations are performed and the effect of external electric field on the fluctuation spectra is studied.« less
  • The force acting on a small absorbing body embedded in a highly collisional plasma with drifting ions is calculated using the linear response formalism. It is shown that the absorption introduces physical effects leading to a drastic reduction of the force. The importance of this result is discussed, mostly in the context of complex (dusty) plasma research, but it can be relevant to many other situations, ranging from astrophysics, thunderclouds, dust in fusion devices, colloidal suspensions, biological systems, etc.