Propagation of a Light-Emitting Wave-Front in a Fine Tube Positive Column Discharge

概要

論文の詳細を見る
The propagation velocity of a light-emitting wave-front is observed to be $u_{\text{p}}\sim 2\times 10^{+5}$ m/s before Townsend breakdown and $u_{\text{p}}\sim 5\times 10^{+6}$ m/s after Townsend breakdown along a discharge tube of inner diameter $r_{\text{o}}\sim 1.2$ mm and length of 900 mm relevant to liquid crystal display television backlighting. Before Townsend breakdown, the origin of this wave is the ambipolar diffusion of plasma flux with the propagation speed $u_{\text{p}}\propto D_{\text{a}}/r_{\text{o}}$ for the plasma bounded by the radius $r_{\text{o}}$ with the diffusion coefficient $D_{\text{a}}$ along the positive column. After Townsend breakdown, the light-emitting wave-front propagates with the electron plasma wave generated by the pulses of driving voltage. The electron plasma wave propagates such a long distance along the tube without damping due to the effect of localized plasma generation by electron impact ionization collisions. The propagation velocity is described by $u_{\text{p}}\sim 2u_{\text{e}}^{2}/u_{\text{d}}$, which is larger than the electron thermal velocity $u_{\text{e}}$ as well as the electron drift velocity $u_{\text{d}}$.
2010-02-25