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To completely characterize the evolving state of a plasma, diagnostic tools that enable measurements of the time-resolved behavior are required. In this study, a gridded ion source with superimposed oscillations was utilized to verify the functionality of a high-speed retarding potential analyzer (HSRPA), at frequencies equivalent to the low freque...
Citations
... III A, various signal processing methods are available for reconstructing TIDFs. These include the empirical transfer function, 27,28,33 time realignment, 13,14 shadow manifold interpolation, 29,30,33 and their variants, with or without discharge forcing. 34 Each method has its own advantages and limitations. ...
... III A, various signal processing methods are available for reconstructing TIDFs. These include the empirical transfer function, 27,28,33 time realignment, 13,14 shadow manifold interpolation, 29,30,33 and their variants, with or without discharge forcing. 34 Each method has its own advantages and limitations. ...
... Further noise reduction in the transfer function can be achieved by averaging the FFTs calculated over sliding time windows 28 when computing the complex series. Despite these enhancements, tests conducted with a perfectly known, controllable, and adjustable ion source, 33 revealed that the Fourier space transfer function method fails to accurately reconstruct noisy sinusoidal signals. This limitation arises because the transfer function reconstruction method remains highly sensitive to experimental noise. ...
This paper presents a technique for reconstructing the temporal evolution of ion distribution functions (IDF) in a Hall thruster using ion currents measured with a retarding potential analyzer. The method involves averaging discharge oscillations with temporal realignment based on the maxima of the discharge current. This technique was applied to ion currents from the experimental ID-Hall 2 thruster, successfully reconstructing the time-dependent ion distribution function in quasi-periodic plasma oscillation regimes. The results indicate that deformations in the integrated ion distribution function can be attributed to the IDF's temporal evolution over a characteristic time equal to the breathing mode oscillation period. This finding suggests the possibility of uncoordinated displacement of ionization and acceleration zones within the discharge. In certain oscillation regimes, the oscillations in ion transit time also appear to have a minor effect on ion acceleration.
