127 research outputs found
Multiply charged ions in hall thruster plasmas
No full textOperation performance and ion beam characteristics related to multiply charged ions in 200 W class Hall thruster plasmas are studied. Our previous studies reported the propellant efficiency larger than unity1, 2 in the cylindrical Hall thruster (CHT) plasma, which may be related to the presence of multiply charged ions. In this presentation, we report the measured result of the fraction of Xe2+ and Xe3+ ions in the CHT plasma (27–31%) that is significantly larger than that in the annular Hall thruster (AHT) plasma (5-8%) under the similar operating conditions3, 4. The specific impulse and thrust are measured to be higher by 1.4 times in the CHT than those in the AHT at 300 V of the anode voltage. It is found that the high values of specific impulse and thrust are related to the high fraction of multiply charged ions and high ionization rate in the CHT. The details of the comparison of the overall performance and beam characteristics associated with multiply charged ions in the AHT and CHT are presented. The large effect on the fraction of multiply charged ions due to the different magnetic field configuration with different coil current directions in the CHT plasma will also be reported
TouchPhoto: Enabling Independent Picture-taking and Understanding of Photos for Visually-Impaired Users
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Characteristics of the Ion Beam and Performance related to Multiply Charged Ions in Annular and Cylindrical type Hall Thruster Plasmas
No full textPerception of Electrostatic Friction Stimuli in Free Surface Exploration
No full textAssuming the use scenario of free exploration on tactile graphics for people with visual impairments, this study investigated how the users perceive electrostatic friction stimuli on contour-based graphical information. We designed and conducted two experiments with 16 participants (8 visually-impaired and 8 sighted). First, we obtained spatial gap detection thresholds between two lines rendered using the electrostatic display. Second, we investigated spatial numerosity judgement on rendered lines on the display. Results demonstrated that the visually-impaired and sighted participants had similar perceptual performance. We summarize the findings and present suggestions for tactile graphics on an electrostatic friction display.1
High-energy tail formation in an ion energy distribution function in cylindrical Hall thruster plasmas
No full textHigh-energy tail formation in an ion energy distribution function in the cylindrical Hall thruster plasma
No full textMultiply Charged Ions and the Performance Characteristics of Annular and Cylindrical Hall Thruster Plasmas
No full textAzimuthal Distribution of Neutral and Electron Densities Reconstructed from Optical Emission Images of Hall Thruster Plasma
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