Fig. 6
From: An in-flight plasma diagnostic package for spacecraft with electric propulsion
Beam profiles in the HIBEX test chamber in Kiel measured with a movable cylindrical Langmuir probe. The shaded regions indicate the core of the beam, i.e. the diameter to which the beam is restricted by the aperture in the screen. (a) Plasma potential, (b) electron density, (c) electron temperature. (The positions <0 and >0 in the plots correspond to the upper and lower half in Fig. 5(a)