High-β plasma behaviour in a canted mirror

A high-0 hot-electron plasma was studied in an asymmetric magnetic mirror device with a variable cant angle. The plasma was produced by microwave heating at a frequency corresponding to cold-electron-cyclotron resonance together with a higher frequency suitable for upper-off-resonance heating. The position of the high-0 plasma annulus was studied as a function of cant angle and was found to correspond approximately to the position of a midplane modulus-B contour. High-0 effects did modify the spatial location of the losses of energetic electrons into the loss cone but had little effect on the coldplasma losses. Destabilization was not observed when the line-tying of the plasma centre was reduced with glass end plates. An asymmetry of the cold-plasma loss with respect to the equatorial plane was observed at small cant angles and an electric field model was conjectured to explain this behaviour.