2026-09-23T13:39:47Z https://www.ideals.illinois.edu/oai-pmh

oai:www.ideals.illinois.edu:2142/85100 2023-07-11 col_2142_5131 col_2142_14800 com_2142_5130 com_2142_14799 com_2142_234

Rodney Burton Rysanek, Filip 2015-09-25T22:34:25Z 2015-09-25T22:34:25Z 10000-01-01 2007 2007 A pulsed vacuum arc discharge emits a plasma as well as macroparticles in the form of micron-sized molten droplets of cathode material. Due to their direction of flight and submicron to 100 mum diameter, these macroparticles often pose a contamination threat for both spacecraft-based thrusters, and thin film deposition systems. The velocity, mass and charge of copper macroparticles emitted by a 100 A arc was experimentally measured, and compared to a model based on thermionic electron emission. The macroparticle velocity was determined by using a time-of-flight velocity filter. Less than 1% of collected particles are larger than 5.7 mum, but they account for 50% of the collected mass. The charge was calculated by measuring particle deflection in a transverse electric field. The model predicts, and the experimental results verify, that the charge on the macroparticles is positive, as compared to the negative charge expected for a DC vacuum arc. Experimental results show a roughly quadratic dependence of particle charge on the particle diameter (q∼D2), with a 1 mum particle having a positive charge of ∼1000 electronic charges (1.6 x 10-16 C), and a 5 mum particle having a charge of ∼25000 electronic charges. The model is particle temperature dependent, and gives q∼D2 at 1750 K and q∼D1.7 at 2200 K. Arguments are also made for limitations on particle temperature due to radiative and evaporative cooling. Made available in DSpace on 2015-09-25T22:34:25Z (GMT). No. of bitstreams: 2 license.txt: 4848 bytes, checksum: 96035ab3f5e1c23cc7138a224ce498bd (MD5) 3270015.pdf: 2914083 bytes, checksum: 79b4792f60dc5a83852c37ea48c7f045 (MD5) Previous issue date: 2007 Embargo set by: Seth Robbins for item 86381 Lift date: Forever Reason: Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs U of I Only 94 p. Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2007. http://hdl.handle.net/2142/85100 (MiAaPQ)AAI3270015 eng Physics, Fluid and Plasma Charging of Macroparticles Ejected From a Pulsed Vacuum Arc text Aerospace Engineering Aerospace Engineering University of Illinois at Urbana-Champaign Dissertation Ph.D.