Photograph of experimental setup. The blue box encloses the microwave circuit.
Magnetic grill and microwave horn attachment (a) disassembled and (b) assembled. The red plane indicates the cut-plane cross section referred to in calculated magnet maps shown later.
Argon plasma photograph taken from bottom of chamber.
(a) Cross section of original ECR source with magnetic field magnitude contours obtained from Ansoft’s Maxwell (two-dimensional) magnetostatic simulation. The thick black line corresponds to the resonance field strength ( for microwave). (b) Cross section of modified ECR source with magnetic field magnitude contours obtained from Ansoft’s Maxwell 2D magnetostatic simulation. The thick black line corresponds to the resonance field strength ( for microwave).
(a) Electric circuit used in double probe measurements. (b) First probe dimensions and (c) second probe dimensions (black, wires; white, ceramic tube).
Electron density (a) and electron temperature (b) variations with pressure.
Plasma properties measured downstream of source. (a) Plasma density; (b) electron temperature.
Mylar sheet with superimposed magnetic flux contours.
Current collection as a function of bias voltage with and without Mylar sleeve.
Independence of current on collection area for sufficiently large collectors.
(a) Magnetic field profile at magnet poles is favorable for grad-B and curvature drift. (b) Holes driven by electron grad-B and curvature drift along poles of magnet. (c) Hole formed by electron grad-B and curvature drift along gaps.
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