title: Energetic-electron-driven instability in the helically symmetric experiment.
abstract: Energetic electrons generated by electron cyclotron resonance heating are observed to drive instabilities in the quasihelically symmetric stellarator device. The coherent, global fluctuations peak in the plasma core and are measured in the frequency range of 20-120 kHz. Mode propagation is in the diamagnetic drift direction of the driving species. When quasihelical symmetry is broken, the mode is no longer observed. Experimental observations indicate that the unstable mode is acoustic rather than Alfvénic.
authors: Department of Physics and Astronomy, University of California, Los Angeles, Los Angeles, California 90095, USA.
authors: C B
authors: CB
authors: Deng
authors: D L
authors: DL
authors: Brower
authors: B N
authors: BN
authors: Breizman
authors: D A
authors: DA
authors: Spong
authors: A F
authors: AF
authors: Almagri
authors: D T
authors: DT
authors: Anderson
authors: F S B
authors: FS
authors: Anderson
authors: W X
authors: WX
authors: Ding
authors: W
authors: W
authors: Guttenfelder
authors: K M
authors: KM
authors: Likin
authors: J N
authors: JN
authors: Talmadge