A visible plasma

Summary form only given, as follows. The authors have obtained a steady-state plasma with the plasma frequency in the visible. Thus, in principle, phenomena such as the production of electron plasma oscillations can be observed visually. The authors have shown that metallic cesium has both a very low value of free electron density, n, due to its bloated atomic size, and a large number of bound electrons (54) that are polarizable and increase the value of permittivity, epsilon , to 1.4165 epsilon /sub 0/, where epsilon /sub 0/ is the permittivity of vacuum. The low value of electron density alone results in a plasma frequency corresponding to ultraviolet light at 3630 AA, but adding in the correction to epsilon /sub 0/ results in a wavelength of 4320 AA, which is in the blue. The authors have succeeded in photographing the blue light penetrating above the cutoff at the plasma frequency.<>