Experimental Observation of Large-Scale Electron Vortex Structures in the Electrostatic Plasma Lens

We describe here the first experimental results of the observation of electron vortex structures in electrostatic plasma lens caused both by unremovable radial gradients of magnetic field and the high radial gradient of electron density. Anharmonic large-amplitude potential waves propagating in azimuth direction are observed. The results of the measurement of electric field distributions enable to establish that electron bunches (arising due to drift instability) contain trapped electrons rotating around the corresponding bunch center with high velocity, in this way making up the vortex. The dominant mechanism resulting in the stabilization of vortex amplitude is established