Ultrafast broadband frequency modulation of a continuous wave reflectometry system to measure density profiles on ASDEX Upgrade
Ultrafast broadband frequency modulation of a continuous wave reflectometry system to measure density profiles on ASDEX Upgrade
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DOI：
10.1063/1.1147517
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发表时间：
1996-12
影响因子：
1.6
通讯作者：
A. Silva;M. Manso;L. Cupido;M. Albrecht;F. Serra;P. Varela;J. Santos;S. Vergamota;F. Eusebio;J. Fernandes;T. Großmann;A. Kallenbach;B. Kurzan;C. Loureiro;L. Meneses;I. Nunes;F. Silva;W. Suttrop
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文献类型：
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作者：
A. Silva;M. Manso;L. Cupido;M. Albrecht;F. Serra;P. Varela;J. Santos;S. Vergamota;F. Eusebio;J. Fernandes;T. Großmann;A. Kallenbach;B. Kurzan;C. Loureiro;L. Meneses;I. Nunes;F. Silva;W. Suttrop
为升级ASDEX，研制了一套反射率测量系统，用于同时测量从剥离层到体等离子体的高场和低场等离子体分布。该系统的独特功能是使用固态稳定的超突然调谐振荡器(低至10μS)对连续波进行超快宽带频率调制，高场和低场侧通道，以及通过光纤链路的完全远程控制操作。由于传输线的特殊设计，采用进出线解耦和单天线结构，优化了系统的接收，消除了杂散反射。超快运行保证了等离子体湍流的影响大大降低。这两个功能决定了诊断的高性能。专用数据采集系统处理宽带操作产生的大量数据。最近的发展包括新频道的运行和自动和准确的频率校准电路。同时，应用先进的数字信号处理技术，获得了湍流等离子体区域(如刮离层)下的高时空分辨率(20μS)的密度分布。实验结果表明，该诊断方法对等离子体径向运动具有很高的灵敏度，对等离子体垂直运动具有很强的容忍性。在ELMY制度下测量的密度分布说明了诊断设备检测快速分布变化的能力。
A reflectometry system has been developed for ASDEX Upgrade to measure the plasma profile from the scrape‐off layer until the bulk plasma, simultaneously at the high and low field sides. Unique features of the system are the ultrafast broadband frequency modulation of a continuous wave using solid state stable hyper abrupt tuned oscillators (down to 10 μs), high and low field side channels and fully remote control operation, via optical fiber links. Due to the special design of the transmission line, with decoupled in going and out going lines and one‐antenna configuration, the system is optimized for reception and spurious reflections are eliminated. The ultrafast operation guarantees that the effect of plasma turbulence is greatly reduced. Both features determine the high performance of the diagnostic. A dedicated data acquisition system handles the large amounts of data generated by the broadband operation. Recent developments include the operation of new channels and an automatic and accurate frequency calibration circuit. Also, advanced digital signal processing techniques were applied to obtain density profiles with high spatial and temporal (20 μs) resolutions under turbulent plasma regions, e.g., the scrape‐off layer. Experimental results are presented showing the great sensitivity of the diagnostic to plasma radial movements and its tolerance to vertical movements of the plasma. Density profiles measured in ELMy regimes illustrate the capabilities of the diagnostic to detect fast profile changes.