The dynamics of long-wavelength(kθ<1.4 cm^(-1)),broadband(20 kHz–200 kHz)electron temperature fluctuations(Te/Te)of plasmas in gas-puff experiments are observed for the first time in HL-2A tokamak.In a relatively...The dynamics of long-wavelength(kθ<1.4 cm^(-1)),broadband(20 kHz–200 kHz)electron temperature fluctuations(Te/Te)of plasmas in gas-puff experiments are observed for the first time in HL-2A tokamak.In a relatively low density(ne(0)■0.91×10^(19)m^(-3)–1.20×10^(19)m^(-3))scenario,after gas-puffing the core temperature increases and the edge temperature drops.On the contrary,temperature fluctuation drops at the core and increases at the edge.Analyses show the non-local emergence is accompanied with a long radial coherent length of turbulent fluctuations.While in a higher density(ne(0)?1.83×10^(19)m^(-3)–2.02×10^(19)m^(-3))scenario,the phenomena are not observed.Furthermore,compelling evidence indicates that E×B shear serves as a substantial contributor to this extensive radial interaction.This finding offers a direct explanatory link to the intriguing core-heating phenomenon witnessed within the realm of non-local transport.展开更多
In J-TEXT tokamak,fast electron bremsstrahlung diagnostic with 9 chords equipped with multichannel analyzer enables detailed studies of the generation and transport of fast electrons.The spatial profiles and energy sp...In J-TEXT tokamak,fast electron bremsstrahlung diagnostic with 9 chords equipped with multichannel analyzer enables detailed studies of the generation and transport of fast electrons.The spatial profiles and energy spectrum of the fast electrons have been measured in two ECCD cases with either on-axis or off-axis injection,and the profiles processed by Abel-inversion are consistent with the calculated power deposition locations.Moreover,it is observed that the energy of fast electrons increases rapidly after turning off the ECCD,which may be attributed to the acceleration by the recovered loop voltage at low electron density.展开更多
Recently,experimental studies on the soft landing of RE current by ohmic(OH)field have been performed in J-TEXT tokamak,as a possible auxiliary method to dissipate the RE current.With optimized horizontal displacement...Recently,experimental studies on the soft landing of RE current by ohmic(OH)field have been performed in J-TEXT tokamak,as a possible auxiliary method to dissipate the RE current.With optimized horizontal displacement control of the RE beam,the toroidal electric field has been scanned from 1.6 to—0.3 V m^-1 during the RE plateau phase.The growth rate of RE currents and the evolution of hard x-ray(HXR)emissions have been studied.It is found that when the toroidal electric field is less than 7-12 times the theoretical critical electric field,the decay of REs could be achieved.The dissipation rate by the ohmic field can reach a maximum value of 3 MA s^-1.Furthermore,the results of HXR spectra analysis indicate the different behaviors of HXR emissions under the condition of different toroidal electric fields.The analysis of the ionized argon emissions and magnetic fluctuations shows that under the condition of different toroidal electric fields,the physical process of RE generation may be different.展开更多
基金Project supported by the National Key Research and Development Program of China(Grant No.2017YFE0301203)the Innovation Program of Southwestern Institute of Physics(Grant No.202301XWCX001)+2 种基金the Sichuan Science and Technology Program(Grant Nos.2023ZYD0014 and 2021YFSY0044)the National Natural Science Foundation of China(Grant No.12175055)the Shenzhen Municipal Collaborative Innovation Technology Program-International Science and Technology Cooperation Project(Grant No.GJHZ20220913142609017)。
文摘The dynamics of long-wavelength(kθ<1.4 cm^(-1)),broadband(20 kHz–200 kHz)electron temperature fluctuations(Te/Te)of plasmas in gas-puff experiments are observed for the first time in HL-2A tokamak.In a relatively low density(ne(0)■0.91×10^(19)m^(-3)–1.20×10^(19)m^(-3))scenario,after gas-puffing the core temperature increases and the edge temperature drops.On the contrary,temperature fluctuation drops at the core and increases at the edge.Analyses show the non-local emergence is accompanied with a long radial coherent length of turbulent fluctuations.While in a higher density(ne(0)?1.83×10^(19)m^(-3)–2.02×10^(19)m^(-3))scenario,the phenomena are not observed.Furthermore,compelling evidence indicates that E×B shear serves as a substantial contributor to this extensive radial interaction.This finding offers a direct explanatory link to the intriguing core-heating phenomenon witnessed within the realm of non-local transport.
基金the National Key R&D Program of China(Nos.2017YFE0302000,2018YFE0309103,2019YFE030-10004,2017YFE0300501,2018YFE0310300,2018YFE0309100)National Natural Science Foundation of China(Nos.11775089,51821005,11905077 and 11575068)the China Postdoctoral Science Foundation(No.2019M652615)。
文摘In J-TEXT tokamak,fast electron bremsstrahlung diagnostic with 9 chords equipped with multichannel analyzer enables detailed studies of the generation and transport of fast electrons.The spatial profiles and energy spectrum of the fast electrons have been measured in two ECCD cases with either on-axis or off-axis injection,and the profiles processed by Abel-inversion are consistent with the calculated power deposition locations.Moreover,it is observed that the energy of fast electrons increases rapidly after turning off the ECCD,which may be attributed to the acceleration by the recovered loop voltage at low electron density.
基金supported by the National Key R&D Program of China(No.2017YFE0302000)the National Magnetic Confinement Fusion Science Program of China(Nos.2015GB111002,2015GB104000)+1 种基金National Natural Science Foundation of China(Nos.11775089,51821005,71762031,11575068,11905077)the China Postdoctoral Science Foundation(2019M652615)。
文摘Recently,experimental studies on the soft landing of RE current by ohmic(OH)field have been performed in J-TEXT tokamak,as a possible auxiliary method to dissipate the RE current.With optimized horizontal displacement control of the RE beam,the toroidal electric field has been scanned from 1.6 to—0.3 V m^-1 during the RE plateau phase.The growth rate of RE currents and the evolution of hard x-ray(HXR)emissions have been studied.It is found that when the toroidal electric field is less than 7-12 times the theoretical critical electric field,the decay of REs could be achieved.The dissipation rate by the ohmic field can reach a maximum value of 3 MA s^-1.Furthermore,the results of HXR spectra analysis indicate the different behaviors of HXR emissions under the condition of different toroidal electric fields.The analysis of the ionized argon emissions and magnetic fluctuations shows that under the condition of different toroidal electric fields,the physical process of RE generation may be different.
