Plasma heating by non-linear wave-Plasma interaction
We simulate the non-linear interaction of waves with magnetized tritium plasma with the aim of determining the parameter values that characterize the response of the plasma. The wave-plasma interaction has a non-conservative Hamiltonian description. The resulting system of Hamilton's equations is integrated numerically using fourth order Runge-Kutta scheme. It is found that for wave amplitude α as low as 0.01Bo the response of the plasma is remarkably different from the prediction of linear response theory. The response cannot be explained in terms of whether or not the wave frequency w is a harmonic of the ion cyclotron frequency Ω. The scaled drift velocity of the ions α and the scaled phase velocity of the waves β were found to be more relevant in explaining the response characteristics. For α >> β, the plasma response is found to be chaotic while for α<< β, the response is either periodic or quasi-periodic. For α ≈ β the waves do not interact with the plasma. The energy deposition (heating) by the waves in the plasma is found to be enhanced when the interaction occurs in the chaotic mode. In this mode, plasma diffusion is negligible suggesting that chaotic interaction of waves with plasma may enhance containment of the plasma.
Journal of the Nigerian Association of Mathematical Physics Vol. 10 2006: pp. 157-166