Nonlinear oscillation dynamics and grid-controlled transition to turbulence in a DC discharge plasma

The present experimental study mainly reports on the controlled development of various anodic structures in the presence of asymmetric electrode geometry and an ambient magnetic field. The visible dynamic transition of layered structures in different DC discharge regimes due to selective confinement of nonthermal electrons by the negatively biased grid enhances the comprehension of intermittent behavior existing in the system. In order to satisfy the requirement for complex structure formations in a higher discharge regime, the study further encourages the investigation of the prerequisite for the route to turbulence via bifurcation. In order to diagnose the creation of anodic structures, the Langmuir probe is used to examine the floating potential oscillations that correspond to the shift from periodic–chaotic to broadband turbulent states. A detailed nonlinear analysis of fast Fourier transform, phase space, continuous wavelet transform, and empirical mode decomposition is applied to explore to study such behavior. In order to obtain mathematical comprehension, simulations of the forced Van der Pol oscillator, a canonical nonlinear model renowned for its rich dynamical behavior under external forcing, are compared with experimental results from the proposed plasma triode system. The results improve our knowledge of nonlinear plasma dynamics and show how grid-induced control modulates the emergence of turbulence, which will greatly help in the future design and regulation of discharge plasmas in various applications requiring stability amidst nonlinear transitions.