Observation of macroscopic stability of weakly magnetized Li+ ion beams near the Brillouin density limit

Macroscopic two-dimensional (2D) images of flowing weakly magnetized lithium (Li+) ion beams are systematically presented. When the beam density approaches the Brillouin density limit, the 2D shape of the flowing Li+ ion beam deforms gradually. Also, the images clearly show not only the m = 1 shift mode but also higher modes of the flowing Li+ ion beams. These observed modes are analyzed by using a Fourier transform method.