A New Theory for Striations with Experimental Verifications

摘要

A new general theory for striated positive columns containing atomic or molecular fill gases is elaborated that gives a unified explanation of both standing striations and cathode-directed and anode-directed moving striations along with the significance of the Novak potential. The p, r, and s striation varieties in neon are explained according to this new theory, including the ionization mechanisms associated with their generation, and the results are experimentally verified via measurements in neon discharges and Penning discharges of neon with argon admixtures. The mathematical model of the positive column derived for this theory shows how an open-loop instability that is an inherent feature of the process maintaining the charged particle density along the column sustains self-excited striations. To illustrate the basic nature of the open-loop instability leading to self-excited striations, a simple analog of the positive column is presented. This new theory therefore contrasts with the widely accepted viewpoint of Pekarek that self-excited striations are caused by closed-loop feedback paths consisting of propagating 'ionization waves' which couple disturbances back to their point of origin with sufficient amplitudes to excite successive ionization waves. Standing striations in RF-excited columns are also explained. (Author)