Initial imprint effect on dynamic mitigation of plasma instability

TL;DR

This paper investigates how initial imprint effects influence the dynamic mitigation of plasma instabilities and demonstrates that pulse shaping can reduce these effects, enhancing instability control.

Contribution

It introduces a method to reduce initial imprint effects in phase-controlled plasma instability mitigation using pulse shaping techniques.

Findings

Pulse shaping reduces initial imprint effects.

Phase control effectively mitigates plasma instabilities.

Initial imprint influences the effectiveness of mitigation.

Abstract

We proposed a dynamic mitigation method for plasma instabilities based on a phase control to mitigate plasma instabilities and to smooth plasma non-uniformities [e.g. Phys. Plasmas, 19(2012)024503]. In plasmas, perturbation phase would be unknown in general, and instability growth rate is discussed. However, if the perturbation is introduced by, for example, an illumination non-uniformity of an input energy driver beam, the perturbation phase would be defined by the driver illumination non-uniformity itself. When the driver axis is controlled by its axis oscillation or wobbling motion, the perturbation phase would be known and controlled. By the superimposition of the growing phase-controlled perturbations, the overall plasma instability growth is mitigated. The dynamic mitigation method is effective to mitigate growths of various plasma instabilities. At the same time, it was found that the phase of the growing perturbations mitigated would be still defined by the initial imprint. In this paper, the initial imprint effect is focused on the dynamic mitigation mechanism in plasmas. The results in this paper demonstrate that the initial imprint effect is reduced by a pulse shaping of the oscillating or wobbling perturbation.