Examples for the visual appearance of striations in glow discharges (after de la Rue and Müller, Phil. Trans. Roy. Soc. Lond., 169, 155, 1878; reproduced from Brown, A short history of gaseous electronic, in Gaseous Electronics Vol.I, Acadamic Press, 1978; image not subject to Copyright regulations)
It is easy to show that with the usual 'theory' for the electron impact excitation cross section, at best 1-2 striation layers should be sharply defined. An explicit measurement of the electric potential and -field distribution through one striation layer (see FIG.11b ) confirms that the excitation process is in fact characterised by a cross section identical to the corresponding radiative resonant scattering process.