Electron Heating of Magnetized Electrode Surfaces

When charged particles, such as electrons, impact an electrode surface in a magnetically insulated transmission line (MITL), we expect an increase in electrode heating. Often the electron impact is modeled as a single impact, that is assuming the electron is absorbed into the bulk electrode material after impact. However, for sufficiently strong magnetic fields near the MITL surface or a sufficiently oblique angle of incidence, one expects that the electrons will conduct cyclotron orbits resulting in multiple impacts at the surface of the electrode. Multiple electron impacts will yield an enhancement in the electrode surface heating compared to a single impact. In this presentation, we derive the conditions for multiple electron impact electrode heating, which include the electron kinetic energy, angle of incidence, electron stopping power of the material, and the strength of the magnetic field for the case of a fully diffused magnetic field in the electrode. We also demonstrate the effects of energy dependent electron stopping power and finite magnetic field diffusion due to realistic material resistivity on electron heating of electrodes.