Parity-breaking parametric decay instability of kinetic Alfven waves in a nonuniform plasma

We demonstrate that in a nonuniform plasma, the parametric decay instabilities of kinetic Alfven waves could be quantitatively and qualitatively different from that in a uniform plasma. Specifically, the decay rate via ion Compton scattering is found to be enhanced, typically, by an order of magnitude. Furthermore, the parity of the decay kinetic Alfven wave spectrum is broken, leading to finite net wave momentum transfer and, consequently, significant convective plasma transport with implications for confinement improvement. That localized absolutely unstable eigenmodes may be excited by a mode-converted pump wave is also presented. Published under an exclusive license by AIP Publishing.

Automated summary

This paper demonstrates that the parametric decay instabilities of kinetic Alfven waves in a nonuniform plasma can be significantly different from those in a uniform plasma. The decay rate via ion Compton scattering is found to be enhanced by an order of magnitude, and the parity of the decay kinetic Alfven wave spectrum is broken, resulting in finite net wave momentum transfer and significant plasma transport.