Arc discharge rotation in external magnetic field-nonuniformities and formation of a nonlinear dynamic system

An arc burning in a mercury vapor discharge tube was exposed to an axial magnetic field, causing arc oscillations which were mostly of a rotary character. The records of the arc current and radiation show features typical for nonlinear dynamic systems, e.g., transitions between many types of periodical or chaotic oscillations. The motion of the arc in various parts of the tube was detected by the photodiode arrays and recorded along with the arc current in the form of long time series. The Fourier analyses of the acquired data, including evaluations of the arc rotation frequency and its phase shifts, mere used to investigate processes interfering with a uniform arc rotation and responsible for the development of the arc as a nonlinear dynamic system.