Experimental and modeling uncertainties in the validation of Lower Hybrid Current Drive
Authors: F. M. Poli
, P. T. Bonoli, M. Chilenski,
R. Mumgaard, S. Shiraiwa, G. M. Wallace
, R. Andre, L.
Delgado-Aparicio, S. Scott, J. R. Wilson, R.W. Harvey, Yu.V.
Petrov
,
M. Reinke, I. Faust, R. Granetz, J. Hughes, J. Rice, J.
Walk
Abstract: This work discusses sources of
uncertainty in the validation of lower hybrid wave current drive
simulations against experiments, by evolving self-consistently the
magnetic equilibrium and the heating and current drive profi les,
calculated with a combined toroidal ray tracing code and 3D
Fokker-Planck solver. The simulations indicate a complex interplay
of elements, where uncertainties in the input plasma parameters,
in the models and in the transport solver combine and - in some
cases - compensate each other. It is concluded that ray-tracing
calculations should include a realistic representation of the
density and temperature in the region between the con fined plasma
and the antenna, which is especially important in regimes where
the LH waves are weakly damped and undergo multiple reflections
from the plasma boundary. It has been found that uncertainties in
the processing of the diagnostic data have as large an eff ect on
the calculations as the model approximations. It is shown that by
comparing the evolution of the plasma parameters in
self-consistent simulations with available data that
inconsistencies can be identifi ed and limitations in the models
or in the experimental data be assessed.
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