Plasma-Return-Current Heating by Relativistic Electron Beams with $\frac{\nu }{\gamma }\sim 10$

We report experimental results of hydrogen-plasma heating using very intense relativistic electron beams with $\frac{\nu }{\gamma }$ up to 10. The beam-plasma interaction process is found to be plasma-return-current heating with strongly anomalous plasma resistivity. Peak plasma energy is 1.5×${10}^{19}$ eV/${\mathrm{cm}}^3$, corresponding to $T_e=2.2\mathrm{}$ keV at $n_e=6.7\mathrm{}\times {10}^{15}$ ${\mathrm{cm}}^{-3\mathrm{}}$.