A Calculation Model of Beam Angular Divergence for EAST Neutral Beam Injector

Distributed thermocouple measurement will be used on EAST neutral beam injection beam angular divergence measurement. In order to obtain calculation model of beam angular divergence: (1) the structure of accelerating electrodes are analyzed, (2) mathematic derivations of beam intensity distribution for neutral beam is given basing on theory of Gaussian distribution, (3) the processing method of experiment data and selection of algorithm are given. The model could point the way to beam angular divergence measurement of EAST neutral beam injection.     

Calculation of Beam Intensity Distribution for the Neutral Beam Injection in EAST

Theoretical beam intensity distribution is derived for the neutral-beam-injection ion source with a multi-slot extraction in EAST. The beam intensity profile, b...     

Achievement of 100 s Long Pulse Neutral Beam Extraction in EAST Neutral Beam Injector

Neutral beam injection (NBI) is recognized as one of the most e®ective means for plasma heating. A 100 s long pulse neutral beam with 30 keV beam energy, 10 A beam current and a 100 s long pulse modulating neutral beam with 50 keV beam energy, 16 A beam current were achieved in the EAST neutral beam injector on the test-stand. The preliminary results suggest that EAST-NBI system initially possess the ability of long pulse beam extraction.     

Conceptual Design of Neutral Beam Injection System for EAST

Neutral beam injection (NBI) system with two neutral beam injections will be constructed on the Experimental Advanced Superconducting Tokamak (EAST) in two stages for high power auxiliary plasmas heating and non-inductive current drive. Each NBI can deliver 2～4 MW beam power with 50～80 keV beam energy in 10～100s pulse length. Each elements of the NBI system are presented in this contribution.     

Analysis of MW-scale Beam Extraction of EAST Neutral Beam Injector Test-stand

Neutral beam injection has been recognized as one of the most effective means for plasma heating. The preliminary data of 50 keV, 100 s and 80 keV, 1 s beam extraction have been obtained on the EAST neutral beam injector (NBI) test-stand. In this paper, beam energy distribution deposited on each heat load component and neutral efficiency of EAST-NBI has been measured using water-flow calorimetry and beam divergence angle and perveance have been analyzed according to the data obtained from the thermocouples installed in the calorimeters.     

A Calculation Model of Beam Power Based on Thermocouple for EAST Neutral Beam Injector

Beam power measurement usually adopts water flow calorimetry (WFC) for neutral beam injector. In this article a calculation model of beam power for EAST neutral beam injector was given basing on thermocouples installed in the calorimeter plate. In order to obtain calculation model: (1) the heat flux of the surface of beam stopping elements was calculated using heat transfer science, (2) the processing method of data obtained from the thermocouple was given, (3) mathematic derivations of beam power is given basing on theory of Gaussian distribution. The model could point another way to beam power measurement of EAST neutral beam injector besides WFC.     

Preliminary Results of Ion Beam Extraction Tests on EAST Neutral Beam Injector

The neutral beam injection (NBI) system is one of the most important auxiliary plasma heating and current driving methods for fusion device.A high power ion beam of 3MW with 80keV beam energy in 0.5s beam duration and a long pulse ion beam of 4s with 50keV beam energy ion beam extraction were achieved on the EAST neutral beam injector on the test-stand.The preliminary results show that the EAST-NBI system was developed successfully on schedule.     

全超导非圆截面托卡马克中性束注入窗口材料活化研究

中性束注入加热为全超导非圆截面托卡马克(EAST)主要辅助加热方式之一.伴随着中性束注入加热,等离子体中子出射强度可达到1014 n/s.由于中性束注入窗口具有较大的开口尺寸,窗口泄露的大量中子可能影响系统的安全稳定运行.本文基于EAST中性束二维模型和蒙特卡洛程序MCNP与材料活化程序FISPACT,研究EAST两条...     

Experimental Results of Ion Beam Extraction of High-Current Ion Source for EAST Neutral Beam Injector

The first campaign of ion beam extraction tests are completed for EAST NBI high current ion source. The hydrogen ion beam with beam voltage of 80 keV is extracted from tetrode accelerator system. During the experiment, the characteristics of arc discharge and ion beam extraction are studied. The arc power reaches 120 kW and the extracted ion beam power reaches 3 MW. The relationship of some key parameters of arc and beam are investigated, and the details are described in this paper.     

Electrical Parameter Measurement System of the Ion Source for EAST Neutral Beam Injector

Neutral beam injection (NBI) is recognized as one of the most effective means of plasma heating. A virtual instrument (VI) has been designed to provide electrical parameter measurement for the ion source of EAST-NBI. The VI is written using the National Instruments LabVIEW graphical programming language. All data acquisition (DAQ) is accomplished using ADLINK DAQ hardware interface and Task-oriented DAQ Driver. The VI can measure filament voltage, filament current, arc voltage, arc current and accelerating voltage etc. The data obtained from the VI are feedback of the ion source operation state and helpful to direct the operation parameter optimization of the ion source.     

Calculation of Neutral Beam Injected Torque and Its Effective Tangency Major Radius for EAST

Toroidal rotation has been recognized to have significant effects on the transport and magnetohydrodynarnic(MHD) stability of tokamak plasmas.Neutral beam injection(NBI) is the most effective rotation generation method on current,tokamak devices.To estimate the effective injected torque of the first neutral beam injection system on EAST,a simplified analytic method was derived.Calculated beam torque values were validated by those obtained from the NUBEAM code simulation.According to the results,for the collisional torque,the effective tangential radius for torque deposition is close to the beam tangency major radius.However,due to the dielectric property of tokamak plasma,the equivalent tangency major radius of the J×B torque is equal to the average major radius of the magnetic flux surface.The results will be useful for the research of toroidal momentum confinement and the experimental analysis of momentum transport related with NBI on EAST.     

Numerical Simulation of Non-Inductive Current Driven Scenario in EAST Using Neutral Beam Injection

For achieving the scientific mission of long pulse and high performance operation,experimental advanced superconducting tokamak(EAST) applies fully superconducting magnet technology and is equiped with high power auxiliary heating system.Besides RF(Radio Frequency) wave heating,neutral beam injection(NBI) is an effective heating and current drive method in fusion research.NBCD(Neutral Beam Current Drive) as a viable non-inductive current drive source plays an important role in quasi-steady state operating scenario for tokamak.The non-inductive current driven scenario in EAST only by NBI is predicted using the TSC/NUBEAM code.At the condition of low plasma current and moderate plasma density,neutral beam injection heats the plasma effectively and NBCD plus bootstrap current accounts for a large proportion among the total plasma current for the flattop time.     

Engineering of Cryopump for Neutral Beam Injection

Neutrals beam injection （NBI） has proven to be a very effective method for plasma heating. A set of positive-ion-based NBI system is being designed, manufactured and tested at ASIPP. The aim of this study was to ascertain the most effective cryocondensation pump structure for the hydrogen NBI system. The parameter design and mechanical design were made to determine the optimum parameters and structure of the cryocondensation pump. The lowest pressure of 7.2 × 10^-6 Pa was achieved in the vacuum chamber, which indicated that this type of liquid helium cryocondensation pump could meet the requirement of the NBI system quite well.     

Predictive Simulations of Plasma Heating and Current Drive by Neutral Beam Injection on EAST

Long pulse and high performance steady-state operation is the main scientific mission of experimental advanced superconducting tokamak (EAST). In order to achieve this objective, high-power auxiliary heating systems are essential. Radio frequency (RF) wave heating and neutral beam injection (NBI) are two principal methods. NBI is an effective method of plasma heating and current drive, and it has been used in many magnetic confinement fusion devices. Based on the plasma equilibrium of EAST (Li et al., Plasma Phys Control Fusion 55:125008, 2013) plus previous EAST experimental data used as initial conditions, the NBI module (Polevoi et al., JAERI-Data, 1997) employed in automated system for transport analysis (ASTRA) code (Pereverzev et al., IPP-Report, 2002) is applied to predict the effects of plasma heating and current drive with different neutral beam injection power levels. At certain levels of plasma densities and plasma current densities, the simulation results show that the NBI heats plasma effectively, also increases the proportions of NB current and bootstrap current among total current significantly.     

First Achievement of Plasma Heating for EAST Neutral Beam Injector

As one of the most effective methods for plasma heating,a neutral beam injector(NBI) achieved plasma heating and current driving for the first time in EAST 2014 experimental campaign.According to the research plan of the EAST physics experiment,the first NBI(EASTNBI-1) has been built and become operational in 2014.In this article,the latest experiment results of EAST-NBI-1 are reported as follows:(1) EAST achieves H-mode plasma in the case of NBI heating alone,(2) EAST achieves 22 s long pulse stable H-mode plasma in the case of sinndtaneous NBI and lower hybrid wave(LHW) heating.The measurement data show that the loop voltage decreased and the plasma stored energy increased obviously.The results indicate that EAST-NBI-1 has achieved plasma heating and current driving,and thus lays a foundation for the construction of EAST-NBI-2,which will be built in a few months this year.     

Predictive Calculation of Neutral Beam Heating Plasmas in EAST Tokamak by NUBEAM Code for Certain Parameter Ranges

A predictive calculation is carried out for neutral beam heating of fusion plasmas in EAST by using NUBEAM code under certain plasma conditions. Results calculated are analyzed for different plasma parameters. Relations between major plasma parameters, such as density and temperature, are obtained and key physical processes in the neutral beam heating, including beam power deposition, trapped fraction, heating efficiency, and power loss, are simulated. Other physical processes, such as current-drive, toroidal rotation and neutron emission, are also discussed.     

Numerical Calculation of the Attenuation of Neutral Beam Injection on HL-2A

The arrangement of the neutral beam line in HL-2A tokamak is introduced. Attenuation of neutral beam injection is analyzed numerically under different plasma conditions： different plasma densities, beam energies, electron temperatures, and impurity concentrations. Both optimized plasma density and beam energy for plasma heating are obtained.     

Development of Distributed Control System for Neutral Beam Injector on EAST

A distributed control system of Neutral Beam Injector(NBI) on the Experimental Advanced Superconducting Tokamak(EAST-NBI) is briefly presented in this paper.The control system is developed in accordance with the experimental operational characteristics of the EASTNBI.The NBI control system(NBICS),which is based on the computer network technologies and classified according to the control levels,consists of three levels:a remote monitoring layer,a server control layer,and a field control layer.The 3-layer architecture is capable of extending the system functions and upgrading devices.The timing system provides the reference clock of the synchronization and interlock for the EAST-NBI system.An interlock system ensures the safety of the experiment operators and field devices.Both of the ion sources of the beamline are designed to operate independently.This lays an important foundation for developing a control system for the second beamline on EAST.Experimental results demonstrate that the NBICS meets functional requirements of the EAST-NBI control,and makes experimental operations visual and automatic.