Electron Cyclotron collisionless interaction during EC-assisted tokamak start-up
Istituto di Fisica del Plasma, CNR, via Cozzi 53 20125 Milano Italy
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Published online: 25 March 2019
In the initial phase of a plasma discharge with EC-assisted breakdown, the wave-particle interaction is nonlinear and wave trapping provides the mechanism for transition from a very low energy state to a much larger energy state. A Hamiltonian adiabatic approach provides the condition for the energy variation to occur in a rigorous way, together with quantitative estimate as a function of the wave frequency, harmonic number, polarisation and EC power and beam width, for the ﬁrst, and second cyclotron harmonic. The interaction is highly localized in space close to the EC resonance. The spatial proﬁle of the energy gain are reported together with the estimates of the width of the radial region where the interaction takes place in the case of a tokamak conﬁguration. The analysis provides a physics based description of the process as well as indications for an optimized experimental setup.
© The Authors, published by EDP Sciences, 2019
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