JET has made unique contributions to the physics basis of ITER by virtue ofits ITER-like geometry, large plasma size and D-T capability. The paper discusses recent JET resultsand their implications for ITER in the are...JET has made unique contributions to the physics basis of ITER by virtue ofits ITER-like geometry, large plasma size and D-T capability. The paper discusses recent JET resultsand their implications for ITER in the areas of standard ELMy H-mode, D-T operation and advancedtokamak modes. In ELMy H-mode the separation of plasma energy into core and pedestal contributionsshows that core confinement scales like gyroBohm transport. High triangularity has a beneficialeffect on confinement and leads to an integrated plasma performance exceeding the ITER Q =10reference case. A revised type I ELM scaling predicts acceptable ELM energy losses for ITER, whileprogress in physics understanding of NTMs shows how to control them in ITER. The D-T experiments of1997 have validated ICRF scenarios for heating ITER/a reactor and identified ion minority schemes(e.g. (~3He)DT) with strong ion heating. They also show that the slowing down of alpha particles isclassical so that the self-heating by fusion alphas should cause no unexpected problems. With thePellet Enhanced Performance mode of 1988, JET has produced the first advanced tokamak mode, withpeaked pressure profiles sustained by reversed magnetic shear and strongly reduced transport. Morerecently, LHCD has provided easy tuning of reversed shear and reliable access to ITBs. Improvedphysics understanding shows that rational g-surfaces play a key role in the formation anddevelopment of ITBs. The demonstration of real time feedback control of plasma current and pressureprofiles opens the path towards fully controlled steady-state tokamak plasmas.展开更多
文摘JET has made unique contributions to the physics basis of ITER by virtue ofits ITER-like geometry, large plasma size and D-T capability. The paper discusses recent JET resultsand their implications for ITER in the areas of standard ELMy H-mode, D-T operation and advancedtokamak modes. In ELMy H-mode the separation of plasma energy into core and pedestal contributionsshows that core confinement scales like gyroBohm transport. High triangularity has a beneficialeffect on confinement and leads to an integrated plasma performance exceeding the ITER Q =10reference case. A revised type I ELM scaling predicts acceptable ELM energy losses for ITER, whileprogress in physics understanding of NTMs shows how to control them in ITER. The D-T experiments of1997 have validated ICRF scenarios for heating ITER/a reactor and identified ion minority schemes(e.g. (~3He)DT) with strong ion heating. They also show that the slowing down of alpha particles isclassical so that the self-heating by fusion alphas should cause no unexpected problems. With thePellet Enhanced Performance mode of 1988, JET has produced the first advanced tokamak mode, withpeaked pressure profiles sustained by reversed magnetic shear and strongly reduced transport. Morerecently, LHCD has provided easy tuning of reversed shear and reliable access to ITBs. Improvedphysics understanding shows that rational g-surfaces play a key role in the formation anddevelopment of ITBs. The demonstration of real time feedback control of plasma current and pressureprofiles opens the path towards fully controlled steady-state tokamak plasmas.
文摘在先进实验超导托卡马克（experimental advanced superconducting Tokamak,EAST）装置上研制多道极向相关反射仪诊断,使系统可同时测量8（径向）×2（极向）个位置的电子密度涨落.该系统选用8个固定输出频率（12.5、13.5、14.5、15.0、15.5、16.0、17.0和18.0 GHz）的介质振荡器作为信号源,源输出的信号通过4倍频器倍频至V波段,通过多个3 d B定向耦合器耦合成一路,入射波通过一个20 d B定向耦合器分为2路,其中,主路微波通过一个角锥天线入射进入等离子体,副路微波作为参考信号.接收天线阵列由2个极向间隔为6 cm的角锥天线组成.参考信号和反射信号与频率为14.2 GHz的介质振荡器4倍频之后的输出信号进行混频,混频后的中频信号分别通过放大器、带通滤波器组件和同相正交解调器进行解调.通过该诊断系统,初步观察到了由低约束模式向高约束模式转换的现象,且在ELMfree阶段,台基梯度区域,出现了持续时间在毫秒量级、频率在40~50 k Hz的相干模.
