Effects of Driver Bandwidth upon Resonantly Heated Electrons

Experimental data are presented which show that increased bandwidth of an electromagnetic driver can reduce the hot-electron temperature due to resonant absorption. This work, done at microwave frequencies, shows that $T_H\propto {\left(\frac{\Delta \omega }{\omega }\right)}^{-0.25\mathrm{}}$. We also observe that the hot-electron density increases with increasing bandwidth such that the heat flux ($Q_H\propto n_H{T_H}^{\frac{3}{2}}$) is nearly constant as a function of bandwidth.