| Plasma characterization of the Marshall Magnetic Mirror (M3) using electrostatic probes techniques is described in detail. Three methods are presented for calculating the plasma density using probe techniques for current collection in the plasma. The first method uses the traditional Langmuir method without regard for a strong magnetic field. The second method assumes a strong magnetic field, restricting current collection to one axis of the probe. The third method uses the Orbit Motion Limited (OML) ion saturation current along with results from the theory of Parker and Murphy (PM) for the collection of electrons. It is shown that the electron collection by the probe follows the ParkerMurphy theory. Analysis of experimental data by the methods mentioned shows that the M3 testbed has at least two electron populations; one is a cold population with a temperature around 7.0 eV, and the second is a warm population with a temperature around 0.3 eV. |
