A gridded retarding pressure sensor for ion and neutral particle analysis in flowing plasmas

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/77187/1/AIAA-1996-2983-582.pd

Ionic and neutral particle transport property measurements in the plume of an SPT-100

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/77071/1/AIAA-1996-2712-716.pd

Identifying charge-exchange collision products within the ion-energy distribution of electrostatically accelerated plasmas

When used in flowing electrostatically accelerated plasmas, electrostatic energy analyzers, such as Retarding Potential Analyzers (RPA’s) or Cylindrical Mirror Analyzers (CMA’s), occasionally yield data which seem implausible: for a known applied plasma acceleration voltage, electrostatic analyzers may indicate populations of ions having voltages much greater than that available through the electrostatic discharge. The process responsible for this phenomenon is resonant charge-exchange (CEX) collisions between ions of different charge species. Through the transfer of electrons, an ion of charge n+n+ can appear in an electrostatic analyzer with equivalent voltage of n-times the available acceleration potential. This paper discusses the phenomena responsible for the appearance of such high-voltage ions in the measured voltage distribution function and presents evidence for such reactions in the flowing xenon plasma produced by a Hall-effect current accelerator designed for spacecraft propulsion. For a 300 V applied potential on the Hall accelerator electrodes, CEX collisions are shown to produce ions having voltages as high as 800 V when measured using an electrostatic analyzer. © 1999 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/69918/2/PHPAEN-6-7-2936-1.pd

Ion energy diagnostics in the plume of an SPT-100 from thrust axis to backflow region

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/77389/1/AIAA-1998-3641-696.pd

Cooperating Agents for 3D Scientific Data Interpretation

Many organizations collect vast quantities of three-dimensional (3-D) scientific data in volumetric form for a range of purposes, including resource exploration, market forecasting, and process modelling. Traditionally, these data have been interpreted by human experts with only minimal software assistance. However, such manual interpretation is a painstakingly slow and tedious process. Moreover, since interpretation involves subjective judgements and each interpreter has different scientific knowledge and experience, formulation of an effective interpretation often requires the cooperation of numerous such experts. Hence, there is a pressing need for a software system in which individual interpretations can be generated automatically and then refined through the use of cooperative reasoning and information sharing. To this end, a prototype system, SurfaceMapper, has been developed in which a community of cooperating software agents automatically locate and display interpretations in a volume of 3-D scientific data. The challenges and experiences in designing and building such a system are discussed. Particular emphasis is given to the agents' interactions and an empirical evaluation of the effectiveness of different cooperation strategies is presented

Two-Axis Laser-Induced Fluorescence of Singly-Charged Xenon inside a 6-kW Hall Thruster

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/90653/1/AIAA-2011-1015-640.pd

Field Asymmetry and Thrust Control in the GDM Fusion Propulsion System

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76831/1/AIAA-2007-5612-220.pd

Alpha Particle Dynamics in Muon-Boosted Fusion Propulsion System

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/77129/1/AIAA-2008-4674-768.pd