5-9 September 2016
Prague Congress Centre
Europe/Prague timezone

P2.036 Power and Particle Deposition Modeling of DIII-D and EAST Neutral Beam Systems

6 Sep 2016, 14:20
1h 40m
Foyer 2A (2nd floor), 3A (3rd floor) (Prague Congress Centre)

Foyer 2A (2nd floor), 3A (3rd floor)

Prague Congress Centre

5. května 65, Prague, Czech Republic
Board: 36
Poster B. Plasma Heating and Current Drive P2 Poster session

Speaker

Brendan Crowley (DIII-D National Fusion Facility)

Description

The Neutral Beam system on DIII-D consists of eight ion sources. The basis of the DIII-D NB system is the Common Long Pulse Source (CLPS). The CLPS is an 80 kV high perveance, deuterium positive ion based system delivering up to 2.5 MW per source. The ion source is a filament driven magnetic bucket design and the accelerator is a slot and rail tetrode design with vertical focusing achieved through tilted grids. A similar neutral beam system with four sources is installed on the EAST machine in Hefei, China. DIII-D is in the process of enhancing the NBI system in several ways: by developing in-shot variable voltage capability, increasing NBI power through increased beam current, and increasing maximum co-injected and off-axis injected power by reconfiguring one beamline for co- and counter-injection as well as off-axis injection.  Also proposed is a novel system to modulate the beam at high frequencies (~100 kHz, ΔV ≤ 1 kV) so the beam effectively becomes an antenna localized to the plasma core. The EAST development efforts are concentrated on achieving long pulse steady state operation. In support of these upgrades, two beam codes have been developed as tools to determine the power loading and particle trajectories onto beamline components and these results are used to determine operating limits and identify risks.  The codes are benchmarked with respect to calorimetry data with further validation of the model input data by Doppler shifted spectroscopy.  Predictions of power loading on key components of the DIII-D and EAST beamlines are made. A speculative hypothesis is presented suggesting that anomalous power deposition in the magnet region is a result of space charge effects.  This effect and its implications for long pulse operation are discussed. *This work supported in part by the US DOE under DE-FC02-04ER5469811 and DE-AC02-09CH11466.

Co-authors

Brendan Crowley (DIII-D National Fusion Facility, General Atomics, San Diego, United States) D. Pace (DIII-D National Fusion Facility, General Atomics, San Diego, United States) H. Torreblanca (DIII-D National Fusion Facility, General Atomics, San Diego, United States) J. Rauch (DIII-D National Fusion Facility, General Atomics, San Diego, United States) J.T. Scoville (DIII-D National Fusion Facility, General Atomics, San Diego, United States) L. Liang (Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, China) Yuanlai Xie (Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, China)

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