Charge of Dust on Surfaces in Plasma

Experimental investigations are reported on the charging of dust particles resting on conducting and insulating surfaces beneath plasma. The experiment is configured to give insight into the behavior of dust on planetary surfaces exposed to solar wind plasma. In the experiments, the surfaces are agitated so that the particles drop through a small hole into a Faraday cup that measures the charge on each dust particle. Both conducting (Ni) and insulating dusts (SiO2, Al2 O3 and JSC-1 lunar regolith simulant) are investigated. The conducting surface is given a bias voltage above the floating potential to create conditions in which the electron flux is dominant or a bias voltage below the floating potential for which the ion flux is dominant. The dust charges more positively in ion-flux-dominant conditions and more negatively in electron-flux-dominant conditions. The insulating dusts retain the charge for a long period of time ( > 1 h) after the plasma is turned off. The charge decays more quickly if the surface is agitated, causing the dust to roll around, or if there is ultraviolet illumination. The conducting dust often has a lower level of charge than the insulating dust because the charge is conducted from the dust particle into the conducting surface. Conducting and insulating dusts on an insulating surface have approximately the same level of charge

[1]  T. Nitter.  Levitation of dust in rf and dc glow discharges , 1996 .

[2]  W. Farrell,et al.  A Dynamic Fountain Model for Lunar Dust , 2005 .

[3]  M. Horányi,et al.  Photoelectric charging of dust particles in vacuum. , 2000, Physical review letters.

[4]  Dale C. Ferguson,et al.  Evidence for Martian electrostatic charging and abrasive wheel wear from the Wheel Abrasion Experiment on the Pathfinder Sojourner rover , 1999 .

[5]  C. Goertz,et al.  Dusty plasmas in the solar system , 1989 .

[6]  M. Horányi,et al.  Measurement of the charging of individual dust grains in a plasma , 1994 .

[7]  J. Lowell,et al.  Contact electrification of metals , 1975 .

[8]  M. Horányi,et al.  Dust grain charging and levitation in a weakly collisional sheath , 2003 .

[9]  E. W. McDaniel,et al.  Collision phenomena in ionized gases , 1964 .

[10]  Jean Cross,et al.  Electrostatics, Principles, Problems and Applications , 1987 .

[11]  Mihaly Horanyi,et al.  Charging of dust particles on surfaces , 2001 .

[12]  Mihaly Horanyi,et al.  Experimental investigations on photoelectric and triboelectric charging of dust , 2001 .

[13]  C. Allen,et al.  JSC-1: A NEW LUNAR SOIL SIMULANT , 1994 .

[14]  Myung-Haing Cho,et al.  Emissive probe current bias method of measuring dc vacuum potential , 1988 .

[15]  P. Lee.  DUST LEVITATION ON ASTEROIDS , 1996 .

[16]  M. Horányi,et al.  Dust transport in photoelectron layers and the formation of dust ponds on Eros , 2005 .

[17]  A. A. Sickafoose,et al.  Contact charging of lunar and Martian dust simulants , 2002 .

[18]  E. Whipple,et al.  Potentials of surfaces in space , 1981 .

[19]  M. Horányi,et al.  Experimental levitation of dust grains in a plasma sheath , 2002 .