D-3He Fusion in the Joint European Torus Tokamak — Recent Experimental Results

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Abstract
A new series of D-3He fusion yield experiment has been performed in the Joint European Torus (JET) using ion cyclotron resonance heating (ICRH) to generate a high-energy 3He tail reacting with a background deuterium plasma. Using recently installed antennas with beryllium screens, radio-frequency power reaching 15 MW can be coupled to the plasma at the fundamental cyclotron resonance of 3He near the magnetic axis. Best results are obtained with 3.5-MA discharges in the double-null configuration with high recycling on the outboard limiters to stay in L mode and to control the plasma density and purity. A record fusion power level of Pfus = 140 kW is obtained, corresponding to a reaction rate of 4.6 × 1016 reaction/s. The amplification factor Q = Pfus/PICRH reaches a maximum of 1.25% at PICRH = 10 MW. The previous best result were Pfus = 700 kW and Q = 1%. Time-resolved measurements show a correlation between fusion power and energy stored in the fast 3He ions in agreement with calculations based on classical slowing down of the 3He ions driven by ICRH to an average energy in the mega-electron-volt range.