Learning Unit Systems Engineering Design Methodology with examples utilizing Advanced Vehicles for Space Transportation
Download 0.76 Mb.
|
 all thrusters derive their thrust by accelerating heavy ions, using an electric field, to high exhaust velocities. Under high magnetic fields, and low densities, the current in the direction perpendicular to the electric field (commonly called the Hall current) can exceed the current along the electric field. As implied by their name, Hall thrusters utilize this Hall current to lock electrons into a nearly collision-less cross-stream drift, leaving the positive ions free to be accelerated by the applied electric field (cf. figure). In a sense, these devices are hybrid electrostatic-electromagnetic accelerators with space-charge neutralization automatically provided by the background of drifting electrons. Because of this, the Hall thrusters are not affected by space-charge limitations. Therefore, Hall thrusters produce higher thrust densities than space charge-limited devices, such as ion thrusters. Two types of Hall thrusters that have high efficiencies and show promise are those that use Bismuth and Xenon as propellants.
The magneto – plasma - dynamic thruster ( Directory: edu -> nycri -> units -> milesthangam edu -> 100 Village Primary School Music Classrooms edu -> Instructions for the Preparation of Camera-Ready Contributions to the Conference Proceedings edu -> Between global market and international and regional cooperation edu -> Biographies of Patriots of Color at The Battle of Bunker Hill John Ashbow Colony: Connecticut Age: 22 Race: Native American Status: Free Rank: Private Position: Rail Fence Unit: Putnam/Durkee edu -> a geospatial Activity a buffer from the Storms edu -> Guide to Preparedness edu -> Social Sciences Teaching Unit Levels 2 6 Environmental Justice milesthangam -> Learning Unit-a robot Analysis and Construction ( robocon ) Project Download 0.76 Mb. Share with your friends:
|