Observations of low frequency oscillations due to transverse sheared flows

This Letter details observations of low frequency (i.e., ω⩽Ωi, where Ωi is the ion cyclotron frequency), coherent instabilities in the Auburn Linear Experiment for Instability Studies (ALEXIS). In the ALEXIS device, which is a 1.8-m long magnetized plasma column, the observed instabilities are excited by the presence of sheared flows in the plasma that are transverse to the axial magnetic field. The instabilities have long azimuthal wavelengths (m⩽2) and are localized in the plasma to regions where the sheared flow is maximized and are anticorrelated to both density gradients and field aligned currents.