Comparison of energetic electron formation in EBT and in minimum-B configurations

The energetic electrons in EBT are observed to form an annulus at the position where the applied microwave frequency is twice the local (cold) electron cyclotron frequency. The axial extent of these rings is not accurately known, but there are indications that they lengthen as the stored energy increases. By contrast, in an open-ended minimum-B geometry the energetic electrons were observed to form in a region in which there was no possibility of second harmonic resonance. The axial extent of the energetic electron population was observed to decrease as the stored energy increased