Ion field emission from micrometer-sized spherical glass grains

• Published in: IEEE transactions on plasma science 2001-04, Vol.29 (2), p.292-297
• Main Authors: Sternovsky, Z., Nemecek, Z., Safrankova, J., Velyhan, A.
• Format: Article
• Language: English
• Subjects: Astronomy; Astrophysics; Basic studies of specific kinds of plasmas; Charging; Cosmology; Density; Dust; Dusty or complex plasmas; plasma crystals; Earth, ocean, space; Electric fields; Electric potential; Electrodynamics; Exact sciences and technology; Field emission; Glass; Grains; Insulation; Insulators; Ion beams; Ions; Particle-theory and field-theory models of the early universe (including cosmic pancakes, cosmic strings, chaotic phenomena, inflationary universe, etc.); Physics; Physics of gases, plasmas and electric discharges; Physics of plasmas and electric discharges; Plasma; Shape; Space charge; Stellar systems. Galactic and extragalactic objects and systems. The universe; Surface charging; Surface discharges; Zinc
• ISSN: 0093-3813; 1939-9375
• DOI: 10.1109/27.923711

An experimental investigation of ion field emission from spherical glass grains in a 1-10 /spl mu/m size range is described. A single dust grain is trapped in an electrodynamic quadrupole and charged positively by a monoenergetic ion beam. The energy of these ions (5 keV) results in a high surface potential and high electric field intensity. A limitation of the surface potential due to ion field emission was observed for the surface field intensity of 3/spl times/10/sup 8/ V/m, which is a considerably lower value than expected. The density of the discharging current was as high as 10/sup -5/ A/m/sup 2/, and increased exponentially with increasing intensity of the electric field. As there are no data of the ion field emission from insulators, we have used the zinc grains for a comparison. Taking into account the irregular shape of used metallic grains, we conclude that the ion field emission from the glass grains starts at a significantly (two orders of magnitude) lower electric field intensity than that from metals. This may lead to the limitation of the attainable surface potential of small insulator grains. The possible effect of the ion field emission on the charging of dust grains in the interplanetary space is discussed.