Article
Instruments & Instrumentation
F. P. Orsitto, S. E. Segre
Summary: In the context of tokamak diagnostics, polarimetry measurements, including Faraday rotation and Cotton-Mouton ellipticity, provide quantitative evaluations of the poloidal magnetic field and plasma density, and can also offer information on the plasma ion mass in plasma similarity experiments. The anisotropy of the index of refraction, mainly related to electron dynamics, plays a key role in deriving polarimetry measurements, which can be influenced by changes in the mass of the main ion. This paper demonstrates that polarimetry measurements indeed depend on the ion mass and this dependency can be detected with current technology.
JOURNAL OF INSTRUMENTATION
(2021)
Article
Instruments & Instrumentation
G. Torrisi, E. Naselli, L. Di Donato, G. S. Mauro, M. Mazzaglia, B. Mishra, A. Pidatella, G. Sorbello, D. Mascali
Summary: Plasma diagnostics play a significant role in ion sources and fusion reactors. This article discusses the design and application of microwave diagnostics approaches and probes to study plasma electron density and behavior.
JOURNAL OF INSTRUMENTATION
(2022)
Article
Instruments & Instrumentation
F. Filippi, D. Fiorucci, A. Fassina, L. Giudicotti, C. Mazzotta, G. Rocchi, R. Rossi, D. Terranova, O. Tudisco, P. Andreoli, M. Cipriani, F. Consoli, P. Gaudio, M. Gelfusa, P. Innocente, G. Mauro, D. Mascali, E. Naselli, F. P. Orsitto, G. Torrisi
Summary: This article introduces a common-path dispersion interferometer/polarimeter suitable for the Divertor Tokamak Test (DTT) facility. The instrument is capable of detecting plasma electron density and magnetic field, and plays a crucial role in the correct operation of the machine and the characterization of the plasma discharge.
JOURNAL OF INSTRUMENTATION
(2022)
Article
Astronomy & Astrophysics
G. Torrisi, E. Naselli, D. Mascali, L. Di Donato, G. Sorbello
Summary: This paper presents the design study of a mm-wave polarimeter for measuring the line-integrated electron density in the PANDORA project, which aims to investigate nuclear beta-decay rates in stellar-like conditions. The paper introduces a method for measurements in a magnetic plasma trap that is intermediate between compact plasma ion sources and large thermonuclear fusion devices. Preliminary measurements at scaled microwave frequencies and on a compact trap are described. The paper also proposes an electromagnetic inverse-scattering-based method for retrieving the electron density profile.
FRONTIERS IN ASTRONOMY AND SPACE SCIENCES
(2022)
Article
Instruments & Instrumentation
Weifeng Deng, Yanming Liu, Rui Li, Jia Zhang, Xiaoping Li, Weimin Bao
Summary: This paper designs a single probe (SP) to study plasma parameters in a high enthalpy ICP-heated wind tunnel. It is discovered that the electron temperature in the core region is about 2.4 eV, while in the edge region it is about 3-4 eV. At the maximum power of the high enthalpy ICP-heated wind tunnel, the electron density reaches 4.34x1013 cm-3. Additionally, the line integral density measured by SP is found to be 0.8 times higher than that measured by the HCN interferometer, indicating a consistent trend between the probe diagnosis and the laser diagnosis results.
JOURNAL OF INSTRUMENTATION
(2023)
Article
Instruments & Instrumentation
Kimika Fushimi, Shusuke Nishiyama, Satoshi Tomioka, Koichi Sasaki
Summary: In this study, saturated cavity ringdown spectroscopy (CRDS) was used to measure the Doppler-free absorption spectrum of atomic hydrogen in an inductively coupled hydrogen plasma. The spectrum was used to estimate the electric field in the sheath region near a biased electrode. The experimental results demonstrate the potential of saturated CRDS for measuring sheath electric fields in plasmas.
JOURNAL OF INSTRUMENTATION
(2023)
Article
Instruments & Instrumentation
K. J. McCarthy
Summary: The TJ-II is a heliac-type stellarator device with a bean-shaped plasma cross-section and excellent diagnostic access. It is equipped with a broad variety and large number of both passive and active diagnostics for thorough plasma monitoring and research.
JOURNAL OF INSTRUMENTATION
(2021)
Article
Instruments & Instrumentation
A. Lizunov
Summary: This study describes the use of visible range optical diagnostic technique to measure the ambipolar electrostatic potential variation in a linear gas dynamic trap, employing Doppler shift of plasma emission lines for observation. By utilizing room temperature hydrogen jet for charge exchange, potential and ion temperature in both central and mirror areas can be measured simultaneously.
JOURNAL OF INSTRUMENTATION
(2021)
Article
Instruments & Instrumentation
N. R. Allen, D. A. Ennis, S. L. Allen, C. M. Samuell, D. M. Kriete, C. A. Johnson, G. J. Hartwell, D. A. Maurer
Summary: A new coherence imaging spectroscopy system has been used to measure impurity ion velocity in the CTH experiment, and its reliability has been confirmed. This system provides high spatial resolution and has shown excellent performance in accuracy and stability based on benchmark testing and additional experiments.
JOURNAL OF INSTRUMENTATION
(2023)
Article
Astronomy & Astrophysics
A. G. de Wijn, J. Cruz de la Rodriguez, G. B. Scharmer, G. Sliepen, P. Sutterlin
Summary: The paper presents the design and performance of a polychromatic polarization modulator for the CRisp Imaging SpectroPolarimeter at the Swedish 1 m Solar Telescope. The trade-offs and procedures discussed in the paper are generally applicable in the development of broadband polarization modulators. The modulator has been operational since 2015, with measured performance close to optimal and differences between design and as-built modulator largely understood.
ASTRONOMICAL JOURNAL
(2021)
Article
Optics
Dale Gottlieb, Oriol Arteaga
Summary: This work presents the design and implementation of a Mueller matrix imaging polarimeter that uses a polarization camera as a detector. The setup provides polarimetric analysis with micrometric resolution and can perform live birefringence imaging. By using a single rotating compensator, the top three rows of the Mueller matrix can be determined after only a few measurements.
Article
Chemistry, Multidisciplinary
Thang L. Nguyen, Soorya Pradeep, Robert L. Judson-Torres, Jason Reed, Michael A. Teitell, Thomas A. Zangle
Summary: Quantitative phase imaging (QPI) is a label-free, wide-field microscopy technique with significant applications in biomedical research. It quantifies biomass distribution and changes by measuring the natural phase shift of light passing through a transparent object. QPI has been used to study cell size, morphology, behavior, drug efficacy, and more, supporting research in development, physiology, neural activity, cancer, and other fields.
Article
Instruments & Instrumentation
D. Mascali, G. Torrisi, L. Di Donato, G. Sorbello, E. Naselli, S. C. Pavone, S. Ceccuzzi
Summary: A new diagnostic method for retrieving the plasma electron density profile in front of the Ion Cyclotron Range of Frequencies (ICRF) antennas is investigated. The method involves solving a non-linear and ill-posed inverse scattering problem. The study extends previous research on compact plasma reactors to large-size fusion reactors.
JOURNAL OF INSTRUMENTATION
(2022)
Article
Instruments & Instrumentation
Yu. Kovtun, A. Goriaev, D. Lopez-Rodriguez, L. Dittrich, P. Petersson, S. Moon, T. Wauters, K. Crombe, S. Moeller, J. Buermans, M. Verstraeten, S. Brezinsek
Summary: This paper provides an overview of the TOMAS plasma diagnostics, which utilizes the Langmuir probe method to measure various plasma parameters. The ion and neutral atom flux and energy distribution are characterized using a Residual Field Energy Analyzer and a Time-of-Flight Neutral Particle Analyzer. The elemental/charge content of the plasma is determined through time-resolved optical emission spectroscopy. Additionally, video diagnostics, including slow video cameras and a high-speed camera, are employed to capture a wide range of plasma events.
JOURNAL OF INSTRUMENTATION
(2023)
Article
Instruments & Instrumentation
J. Svoboda, J. Cavalier, O. Ficker, M. Imrisek, J. Mlynar, M. Hron
Summary: Tomotok is a Python package focused on tomographic inversion of tokamak plasma radiation, providing multiple algorithms and a user-friendly interface. The software is planned to be released as open source to enable global application on different devices. In addition to inversion methods, it also offers auxiliary content and tools for creating simple synthetic diagnostic systems.
JOURNAL OF INSTRUMENTATION
(2021)
Article
Physics, Fluids & Plasmas
X. Z. Gong, A. M. Garofalo, J. Huang, J. P. Qian, A. Ekedah, R. Maingi, C. T. Holcomb, F. K. Liu, Y. P. Zhao, B. J. Xiao, J. S. Hu, C. D. Hu, L. Q. Hu, M. Wang, H. D. Xu, E. Li, L. Zeng, Q. Zang, H. Q. Liu, B. Lyu, Q. P. Yuan, K. D. Li, B. Zhang, J. Y. Zhang, T. Q. Jia, M. Q. Wu, J. L. Chen, X. Zhu, M. H. Li, X. J. Zhang, L. Zhang, Y. M. Duan, L. Wang, R. Ding, Y. W. Sun, G. S. Xu, Y. F. Liang, N. Xiang, B. N. Wan, J. G. Li
Summary: A recent EAST experiment has demonstrated long pulse steady-state high plasma performance and core-edge integration with multi-RF power and current drive, achieving high density and strong confinement.
Article
Physics, Fluids & Plasmas
B. N. Wan, X. Z. Gong, Y. Liang, N. Xiang, G. S. Xu, Y. Sun, L. Wang, J. P. Qian, H. Q. Liu, B. Zhang, T. Y. Xia, J. Huang, R. Ding, T. Zhang, G. Z. Zuo, Z. Sun, L. Zeng, X. J. Zhang, Q. Zang, B. Lyu, A. M. Garofalo, G. Q. Li, K. D. Li, Q. Q. Yang
Summary: Since the last IAEA-Fusion Energy Conference, substantial progress has been made in the development of the Experimental Advanced Superconducting Tokamak (EAST) research program, focusing on the long-pulse steady-state high beta H-mode scenario. Various control schemes have been developed to sustain detachment and suppress ELMs, and important milestones have been achieved in terms of plasma parameters and key technologies. The operational domain of the steady-state H-mode plasma scenario has been expanded, and advancements have been made in divertor technology and heating schemes. EAST has successfully sustained a long-pulse high beta H-mode discharge similar to the CFETR fusion power operation scenario, and helium operation has been achieved for the first time.
Article
Physics, Multidisciplinary
Wenmin Zhang, Ling Zhang, Yunxin Cheng, Shigeru Morita, Zhengxiong Wang, Ailan Hu, Fengling Zhang, Yanmin Duan, Tianfu Zhou, Shouxin Wang, Haiqing Liu
Summary: In this study, the EUV spectra emitted from iron, copper, and molybdenum ions during EAST discharges were measured. It was found that the spectra of highly ionized states of iron, copper, and molybdenum appeared in discharges with high electron temperature. Two unresolved transition arrays and six new spectral lines were also identified.
Article
Physics, Fluids & Plasmas
Yunxin Cheng, Ling Zhang, Shigeru Morita, Xiuda Yang, Ailan Hu, Wenmin Zhang, Fengling Zhang, Zong Xu, Zhenwei Wu, Qing Zang, Yanmin Duan, Shuyu Dai, Mao Wang, Handong Xu, Xiaojie Wang, Xinjun Zhang, Chengming Qin, Haiqing Liu, Liqun Hu
Summary: The spectral intensities emitted by high-Z metal impurity ions in EAST plasmas have been investigated, and their radial profiles have been analyzed. The density profiles of these ions under different heating conditions have also been studied, revealing their behavior.
IEEE TRANSACTIONS ON PLASMA SCIENCE
(2022)
Article
Instruments & Instrumentation
C. P. Li, Y. Yao, Z. H. Li, L. Cheng, Y. Zhang, H. Q. Liu
Summary: In this paper, a microwave IQ demodulation method for breast tumor detection is proposed. The method accurately identifies breast tumors by analyzing the amplitude information of microwave signals. Experimental and simulation results show the feasibility of the method and its ability to distinguish different tumor models.
JOURNAL OF INSTRUMENTATION
(2022)
Article
Physics, Fluids & Plasmas
X. M. Zhong, X. L. Zou, A. D. Liu, Y. T. Song, G. Zhuang, E. Z. Li, B. Zhang, J. Zhang, C. Zhou, X. Feng, Y. M. Duan, R. Ding, H. Q. Liu, B. Lv, L. Wang, L. Q. Xu, L. Zhang, H. L. Zhao, Q. Zang, T. Zhang, B. J. Ding, M. H. Li, C. M. Qin, X. J. Wang, X. J. Zhang
Summary: Quasi-periodic pedestal burst instabilities (PBIs) have been identified during the I-mode to H-mode transition in the EAST Tokamak, with studies suggesting that an increase in density gradient may trigger PBIs. These results provide important precursors for controlling the I-H transition.
Article
Instruments & Instrumentation
H. Lian, H. Q. Liu, D. L. Brower, W. X. Ding, Y. Huang, S. X. Wang, W. M. Li, Y. Q. Chu, R. J. Zhu, Y. X. Jie
Summary: Vertical position stability is crucial for safe and reliable plasma operation in long-pulse fusion devices. This paper compares the non-inductively determined vertical position achieved by line-integrated interferometer and polarimeter measurements with the inductive flux loop method. The results show that the non-inductive measurement is more robust than flux loops after a certain time and propose using the non-inductive system for real-time vertical position control in the next experimental campaign.
REVIEW OF SCIENTIFIC INSTRUMENTS
(2022)
Article
Physics, Fluids & Plasmas
Y. Wang, K. Hanada, H. Liu, X. Gao, Y. Jie, Y. Li, M. Li, C. Wu, Y. Hu, K. He, B. Zhang, L. Zhang, Q. Zang, T. Zhang, T. Zhou, L. Yu, R. Liang, Y. Chu, J. Xie
Summary: Experimental and theoretical analyses were conducted to investigate the mechanism of hot spot formation and found that reducing the gap between separatrix and X-point is an effective way to prevent impurity emission from plasma-facing materials. This effectiveness was confirmed quantitatively by simulations and experiments.
Article
Physics, Fluids & Plasmas
Y. Zhang, X. D. Zhang, Q. L. Qiu, J. Zhang, B. Li, L. Chen, Z. P. Luo, J. P. Qian, L. Wang, H. Q. Liu, L. Y. Meng, X. Liu, B. Zhang, B. Shen, Q. P. Yuan, B. J. Xiao, X. Z. Gong, G. S. Xu, J. S. Hu, K. Lu, X. C. Wu, Y. T. Song
Summary: This paper proposes a novel divertor concept, the fish tail divertor, for reducing the surface temperature on the tokamak divertor plate and the temperature caused by edge localized modes. Experimental results demonstrate the capability of strike point sweeping on the plate at a frequency range of 10 to 100 Hz using an oscillating magnetic field. By applying a coil current of several percent of plasma current, a strike point movement of 5-6 cm is achieved, leading to a significant reduction of divertor surface temperature. The concept shows potential application in fusion reactors.
Article
Physics, Fluids & Plasmas
Y. Q. Chu, B. S. Zhang, P. Li, X. D. Yang, H. Q. Liu, Y. X. Jie, C. B. Wu, W. M. Zhang, K. D. Li, T. F. Zhou, L. He, Q. Zang, H. Lian, F. B. Zhong, R. J. Zhu, L. F. Zhang, K. Hanada
Summary: Improved confinement caused by Ne injection is investigated in EAST. The safety factor q profile and electron-scale turbulence are studied with a polarimeter-interferometer system and CO2 laser collective scattering system in a series of Ne injection experiments in EAST. Ne with a suitable injection rate can lead to negative magnetic shear in the plasma core, which promotes electron-scale turbulence suppression. The continuous injection of Ne under the reversed shear condition further reduces the electron-scale turbulence intensity. Core electron temperature increase and confinement improvement are observed.
Article
Physics, Fluids & Plasmas
Erzhong Li, Y. Chen, H. Qu, T. Zhou, F. Chen, L. Zhang, H. Wang, Y. Duan, H. Liu, B. Shen
Summary: Recently, magneto-hydrodynamic instabilities have been observed in various experimental scenarios using a gas electron multiplier (GEM) camera installed on the Experimental Advanced Superconducting Tokamak (EAST). The GEM camera, placed outside the EAST vacuum chamber, records x-ray photons through a beryllium window, providing valuable data for the analysis of neoclassical tearing mode (NTM) onset and plasma disruption dynamics in the presence of magnetic islands. Although not directly compared to theory and simulations, the GEM camera, in conjunction with other diagnostics, reveals the significance of electron dynamics in NTM and plasma disruption. This is meaningful for understanding and modeling the disruption instability of fusion plasmas.
PLASMA PHYSICS AND CONTROLLED FUSION
(2023)
Article
Physics, Fluids & Plasmas
Wenbin Liu, Kangning Geng, Long Zeng, Weiwen Xiao, Kaixuan Ye, Tao Zhang, Bin Cao, Xiang Zhu, Tian Tang, Haiqing Liu, Ang Ti, Hailin Zhao, Zhe Gao, Yi Tan, Chu Zhou, Ah Di Liu, Muquan Wu, Baolong Hao, Hang Li, Guoqiang Li, Xiang Gao
Summary: A coherent mode (CM) induced by SMBI was observed in Ohmic plasmas of EAST tokamak, which existed in the fluctuation spectra of electron temperature and density but not in the Mirnov fluctuation spectrum. The CM had multiple discrete frequencies between 5 to 20 kHz, occasionally dominated by a single frequency. It was found to be correlated to a high local transport level but did not have a clear influence on global confinement.
PLASMA PHYSICS AND CONTROLLED FUSION
(2023)
Article
Physics, Fluids & Plasmas
Y. F. Wang, K. Hanada, D. Sakurai, H. Q. Liu, T. Lan, X. Gao, X. H. Wu
Summary: This study aims to solve the fringe jump problem in the polarimeter-interferometer (POINT) diagnostics system of the Experiment Advanced Superconducting Tokamak (EAST) by proposing a support vector machine model for electron density fringe jump detection and correction. The established model efficiently classifies the fringe jump data from the raw measurement data, corrects it, and greatly improves the correction efficiency and precision of electron density data from the POINT system. It is expected to be embedded into the plasma control system for more accurate real-time electron density feedback control.
PLASMA PHYSICS AND CONTROLLED FUSION
(2023)
Article
Nanoscience & Nanotechnology
Shanshan Pan, Yanmin Duan, Liqing Xu, Yan Chao, Hailin Zhao, Haiqing Liu, Shouxin Wang, Ling Zhang, Yuqi Chu, Wenmin Zhang, Kaixuan Ye, Liqun Hu
Summary: Accumulation of high-Z impurities in the plasma core can adversely affect plasma performance and trigger sawtooth crashes and tearing modes (TMs) in EAST. Experimental observations in the EAST tokamak show that a large sawtooth crash can trigger m/n = 3/2 and m/n = 2/1 TMs under the condition of high-Z impurity accumulation. This study focuses on the relationship between impurities, sawtooth crashes, and TMs, revealing that impurity transport after a sawtooth crash plays a crucial role in the destabilization of TMs.
Article
Nanoscience & Nanotechnology
J. Y. Li, Z. X. Liu, W. Zhang, Z. W. Ma, X. Gao, G. Q. Li, H. Q. Liu, M. F. Wu, Y. J. Liu, C. C. Deng, P. C. Li, K. N. Yang, X. Y. Yin, H. Li, J. L. Xie, T. Lan, W. Z. Mao, A. D. Liu, C. Zhou, W. X. Ding, G. Zhuang, W. D. Liu, EAST Team
Summary: The pressure crashes observed in shot No. 71326 in the Experimental Advanced Superconducting Tokamak are numerically investigated and found to be caused by the nonlinear evolution of the m/n = 2/1 double tearing mode. The stability of the mode based on the safety factor (q) profile is analyzed, and it is concluded that the original q profile is inconsistent with the actual profile due to q measurement uncertainty. The influence of plasma rotation and the two-fluids effect is also discussed.
