Charging of Macroparticles Ejected From a Pulsed Vacuum Arc
Rysanek, Filip
This item is only available for download by members of the University of Illinois community. Students, faculty, and staff at the U of I may log in with your NetID and password to view the item. If you are trying to access an Illinois-restricted dissertation or thesis, you can request a copy through your library's Inter-Library Loan office or purchase a copy directly from ProQuest.
Permalink
https://hdl.handle.net/2142/85100
Description
Title
Charging of Macroparticles Ejected From a Pulsed Vacuum Arc
Author(s)
Rysanek, Filip
Issue Date
2007
Doctoral Committee Chair(s)
Rodney Burton
Department of Study
Aerospace Engineering
Discipline
Aerospace Engineering
Degree Granting Institution
University of Illinois at Urbana-Champaign
Degree Name
Ph.D.
Degree Level
Dissertation
Keyword(s)
Physics, Fluid and Plasma
Language
eng
Abstract
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.
Use this login method if you
don't
have an
@illinois.edu
email address.
(Oops, I do have one)
IDEALS migrated to a new platform on June 23, 2022. If you created
your account prior to this date, you will have to reset your password
using the forgot-password link below.
