Recent experimental results and modeling of RF heating of ([sup 3]He)-D JET plasmas: RF as a tool to study transport

Abstract

D plasmas with 3 He minorities have sharp, thin ion-ion hybrid layers that enable to efficiently excite short wavelength branches that are subsequently damped by fairly well localized electron Landau and TTMP absorption. Depending on the minority concentration chosen, ion minority heating or electron mode conversion damping is dominant. Recent experiments have been devoted to the study of ( 3 He)-D JET plasmas. One aspect of those experiments -using RF heating as a tool -is the study of the response of the plasma to RF power modulation, allowing to examine the fate of the RF power and to diagnose particle and energy transport. The present paper gives a very brief summary of a subset of these experiments. The focus will largely but not exclusively be on understanding ITB physics. The adopted probing methods are more generally applicable, though.

Overview of recent results on Heating and Current Drive in JET

“…Simulations predicted that D beam particles should be accelerated up to 200keV, well above the source energy, and is confirmed by observations from NPA and γ-spectroscopy. Fast D tails were also observed during mode conversion studies in D ( 3 He) plasmas heated with 130keV D-NBI with gradually increasing 3 He concentrations [16]. At a concentration of about 18%, the time of flight neutron diagnostic TOFOR [17] detected an unexpected fast particle population.…”