Analysis on the azimuthal velocity fluctuation of drift-wave turbulence and zonal flow via dynamic programming based time-delay estimation technique in a linear magnetized plasma device

Abstract

The effective measurement of plasma turbulence flow field is of great help for better understanding the turbulence in magnetically confined plasmas, and experimentally verifying the theoretically predicted phenomenon such as zonal flows. In this article, the dynamic programming based time-delay estimation technique is employed for the first time to estimate azimuthal velocity fluctuation of drift-wave turbulence in a linear magnetized plasma generated via a hot cathode plasma source. Analysis results clearly reproduce the zonal flow structure which is spontaneously generated by nonlinear energy transfer from the drift-wave turbulence. Moreover, via the comparison among the zonal flow (ZF) characteristics estimated respectively by the turbulent fluctuations of plasma located in different frequency regions, we further evaluate the dependences of accuracy and response for estimating ZF property using this newly developed time-delay estimation algorithm on the level of relative incoherent noise in the carrier waves. This work provides an example and reference value for deeper exploration on plasma turbulence and in particular the relevant flow field with the help of the dynamic programming based time-delay estimation technique.