Research on Electron Cloud State of Space Charge Lens

The variation curve of magnetic induction in an axial symmetry magnetic plane of a new space charge lens was analyzed. Through combination of the magnetic mirror field distribution and electron Boltzmann distribution, the second order Poisson equation was solved and potential distribution of the electron cloud in the state of ideal spatial magnetic lens was obtained by fourth-order Runge-Kutta formula. Based on the magnetic field of magnetic mirror, the variation tendency of magnetic confinement factor along the z axis direction of the space charge lens central axis was analyzed. Effects of central electron density, magnetic confinement factor and electron temperature on electron cloud state were numerically simulated. Results show that the electron concentration in the vicinity of the space charge lens central axis tends to be clear with the increase of magnetic confinement factor. The higher electron temperature is, the more actively do electrons move, the larger diffuse space is, the less obvious electron concentration near the center of the space charge lens is.