Glow Discharge with Confinement of Electrons in an Electrostatic Trap

Theory based on the concept of the gas ionization cost $W$ is found to be in a good agreement with experimental study of the glow discharge with electrostatic trap in the gas pressure range 0.001-10 Pa. When the mean ionization length $\lambda $ of emitted by the cathode electrons exceeds the trap width $a=$4$V$/$S$, where $V $is the trap volume and $S$ is area of the trap boundary, and their energy relaxation length $\Lambda =$(\textit{eU}$_{c}$/$W)\lambda $, where $U_{c}$ is cathode fall of potential, is lower than the trap length $L=$4$V$/$S_{o}$, where $S_{o}$ is output aperture of the trap, $U_{c}$ is independent of the pressure $p$. In this middle pressure range due to multiplication of fast electrons in the cathode sheath $U_{c}$ diminishes about 2 times from its maximum W/e$\gamma $, where $\gamma $ is coefficient of ion-induced electron emission, with the discharge current reduction. At $\Lambda $\textgreater $L$ the cathode fall $U_{c}$ rises from hundreds to thousands of volts and $p$ tends to the discharge extinction pressure $p^{ex}$, at which the ionization length $\lambda $ of electrons with energy equal to the energy of electrons emitted by the cathode in the middle pressure range is equal to $L$.