Jinxing Zheng

Chinese Academy of Sciences | CAS · Institute of Plasma Physics

With the development of high-temperature superconducting material technology, the structure and performance of superconducting machines have met the requirements of large-scale use. Compared with conventional motors, the power density of superconducting motors can reach more than 10 kW/kg. Additionally, it has higher efficiency and torque. In this...

The Energy Selection System (ESS) with achromatic capability is essential for a cyclotron-based proton therapy facility. Its purpose is to match the degraded beam to the downstream beam delivery system. In contrast to beam optics calculations using hard-edge and linear transport, the actual fringe field of the magnet and higher-order aberrations of...

In view of the fact that the fusion power of fusion reactor is proportional to the fourth power of the toroidal magnetic field, the design of toroidal field (TF) magnetic system is particularly important for achieving higher operating parameters. In order to meet the confinement requirements of high plasma parameters, the high field region of the T...

Since the invention of rockets, mankind has been constantly trying to explore the universe. It was not until the beginning of the last century that electric propulsion technology was introduced. With the same weight of fuel consumed as chemical propulsion, electric propulsion technology can transport a spacecraft to a more distant universe. With it...

Iron-based superconductors (IBS) are very promising candidates for high-field applications owing to their ultrahigh upper critical field and very small electromagnetic anisotropy. For practical applications, it is essential to develop...

A proton therapy equipment named SC200 is developing in the Institute of Plasma Physics Chinese Academy of Sciences (IPP, CAS) and Hefei CAS Ion Medical and Technical Devices Co., Ltd. In order to develop a light weight gantry for proton therapy, the Canted Cosine theta (CCT) superconducting magnet was considered to apply in the superconducting gan...

Comprehensive Research Facility for Fusion Technology (CRAFT) is a comprehensive research platform for the research and development of the key components of the fusion reactor in China, among them, the Toroidal Field (TF) superconducting magnet system is an important part of the facility. The design and analysis of high-temperature superconducting...

Magnetoplasmadynamic thrusters (MPDTs) are characterized by their high specific impulse, high thrust, and long operational life. Hence, they are promising candidates as space electric thrusters for deep space exploration, such as for future interstellar voyages. To improve the performance of MPDTs, this article investigates the potential to enhance...

In recent years, EAST has achieved a 60-s scale steady-state plasma operation (SSO), which is electron dominant heated by the electron cyclotron wave and low hybrid wave. Substantial progresses have been made in the development of long-pulse operation, such as active control of radiative divertor, edge localized mode (ELM) suppression, and He plasm...

The China Fusion Engineering Test Reactor (CFETR) is the next step in China's roadmap for magnetic confinement fusion development. It aims to bridge the gap between the ITER fusion experimental reactor and the demonstration fusion power reactor (DEMO). The CFETR will be operated in two phases. Phase I aims to achieve fusion power of 50–200 MW, Qpla...

Large-scale complex needs high performance SMES system with 5 kA-level current carrying and kA/s current ramping rate (such as particle accelerator complex), the inductance of which should be as small as possible (<<1H) to reduce the terminal voltage and realize ideal energy evacuation. This paper introduces the world’s first application of double...

Proton treatment may deliver a larger dose to a patient’s skin than traditional photon therapy, especially when a range shifter (RS) is inserted in the beam path. This study investigated the effects of an RS on skin dose while considering RS with different thicknesses, airgaps and materials. First, the physical model of the scanning nozzle with RS...

High temperature superconducting (HTS) magnets often work at high energy density and have slow quench propagation speed, so a quench will present a serious risk to the safety of magnets. The quench protection method based on the dump resistance can effectively reduce the current and release the energy in the HTS magnets. However, too large dump res...

Toroidal field (TF) superconducting magnets are the key components of the China Fusion Engineering Test Reactor (CFETR). While the TF magnets operate in a steady-state, they are located in a time-varying poloidal field environment, which may lead to AC losses. In this paper, the AC losses of a CFETR TF magnet during excitation and plasma disruption...

Fusion energy is a promising source of clean energy, which could solve energy shortages and environmental pollution. Research into controlled fusion energy has been ongoing for over half a century. China has created a clear roadmap for magnetic confinement fusion development, where superconducting tokamaks will be used in commercial fusion reactors...

Current-limiting superconducting cable uses the quench resistance of superconductor under short-circuit current to improve the short-circuit impedance of the system. In this paper, the design of current-limiting 10 kV three-phase tri-axial superconducting cable is studied. The design methods of cable conductor layer, insulation layer and current-li...

China Fusion Engineering Test Reactor (CFETR) is a national scientific research project which is aimed to initially build fusion energy production up to 2×108 W and to eventually reach relevant power level 1×109 W of DEMO. The major and minor radius of CFETR are 7.2 m and 2.2 m, respectively. As one of the most important components, a full-sized CF...

High-performance superconducting joints are essential for the continuous and stable operation of superconducting magnet systems to generate stable magnetic fields, because the local heating from resistive losses can cause the superconductor to enter an unstable regime and result in quench. The China fusion engineering test reactor has five internal...

Proton therapy facilities require a beamline that effectively delivers particles to a nozzle that forms symmetric and achromatic beam spots. In the gantry lattice of the SC200 facility, the magnetic components are designed with a compact layout due to space constraints. This makes it important to properly deal with fringe fields and their interfere...

The new superconducting proton therapy facility consists of a dedicated 200 MeV superconducting cyclotron, new beamlines, a 360° gantry and a fixed beam room for eye treatment. A degrader and laminated magnets in the beamline enable rapid energy changes to modulate the range of the scanning pencil beam applied to patients. In the design of the syst...

The significant advantage of proton therapy over other particle-based techniques is in the unique physical characteristics of the Bragg peak. It can achieve a highly conformal dose distribution and maximize the probability of tumor control by varying the irradiation energy. Most proton facilities use cyclotrons for fixed energy beam extraction and...

Design and implementation of efficient p-type transparent conducting (TC) oxides with excellent performance are the global material challenge. The strategy of “chemical modulation of the valence band” triggers the enthusiasm for p-type TC delafossite CuMO2. However, the low conductivity of previous CuMO2 films obstructs the development of delafossi...

Superconducting magnet is the key component used as the magnetic nozzle to improve the performance of the magnetoelectric thruster. Compared to the traditional copper or permanent magnet, it has high current density and uniform characteristics. Based on space application requirements of the magnetic nozzle for magnetoelectric thruster, a miniaturiz...

A 176 A/mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> , compactness racetrack NbTi Supercon-ducting coil has been developed in Institute of Plasma Physics, Chinese Academy of Sciences. The purpose of this research is to further enhance the levitate and guide force for superconducting magle...

High magnetic fields play a critical role in the development of modern science and technology, breeding many significant scientific discoveries and boosting the generation of new technologies. In the last few years, China has untaken a great deal of work on the application of Ultra-High-Field (UHF) superconducting magnet technology, such as for the...

High-temperature superconducting material is a promising candidate to fabricate superconducting magnet for magnetic confinement fusion reactors. The DPA number of the 1 µm thick superconducting layer in a high temperature superconducting tape under neutron irradiation needs to be calculated to predict the property changes. The DPA cross sections, w...

Global development has been heavily reliant on the overexploitation of natural resources since the Industrial Revolution. With the extensive use of fossil fuels, deforestation, and other forms of land-use change, anthropogenic activities have contributed to the ever-increasing concentrations of greenhouse gases (GHGs) in the atmosphere, causing glo...

Higher magnetic fields are always favoured in the magnetoplasmadynamic thruster (MPDT) due to its superior control of the plasma profile and acceleration process. This paper introduces the world's first integrated study on the 150 kW level AF-MPDT equipped with a superconductive coil. A completely new way of using superconducting magnet technology...

CFETR (China Fusion Engineering Test Reactor) is in its engineering design now. There are two options for divertor, helium-cooled and water-cooled, the water-cooled one was focused in this paper. The upgraded divertor geometry has larger parameters in several directions, which was proposed from the beginning of 2020. Especially, the outer leg (the...

China fusion engineering test reactor (CFETR), based on ITER technology and bridged between ITER and DEMO, has been supported by China government to start technologies R&D and engineering design. The field of CFETR at plasma core is 6.5 T, maximum field of TF coil is about 14.8 T. TF coil is wound by Nb3Sn and NbTi CIC conductors. Coil weight is ab...

Conductor on round core (CORC) cables with the features of flexibility and a high engineering current density have been a potential candidate for high magnetic field magnets and accelerator magnets. In these applications, reducing the magnetization loss generated in superconductors is essential in the process of design. CORC cables fabricated by mu...

With excellent mechanical properties and electromagnetic prop-erties, compact superconducting cables are considered as poten-tial candidates for large capacity power applications and fusion magnets. In this paper, the concept of a novel compact cable, conductors in tube (CIT) cable is introduced from the aspect of design, fabrication, and performan...

Eddy currents induced on the Toroidal Field (TF) coil case during a plasma disruption will cause Joule losses. The analysis of eddy current loss is very important for the safety of the TF coils and cryogenic system. Eddy currents on the TF coil case are related to the decay mode of the plasma and the shielding effect of the vacuum vessel. The magne...

The second-generation high-temperature superconductor REBCO is one of the most valuable candidates that meet the requirements of future magnetic confinement fusion device. Quench behavior of an improved high-current REBCO composite conductor is simulated by a 1-D finite element method. Indium-tin alloy foil placed in the gap between stabilizer, jac...

We report here a record 4.6 T trapped field generated by high temperature superconducting (HTS) persistent current loops using a HTS ring structure. By stacking 200 HTS rings into a compact magnet 90 mm in diameter, we performed a field cooling magnetisation at 25 K. The main advantage of the new magnet compared to existing trapped field HTS magnet...

Equilibrium is essential in the design of the Chinese Fusion Engineering Test Reactor (CFETR). It is based on the principle underlying various physical and engineering issues, such as vertical instability, core plasma physics, divertor physics and design, etc. Built on the 0-D parameters with elongation κ∼2.0 using the equilibrium code TEQ, series...

For proton pencil beam scanning (PBS) technology, the accuracy of the dose distribution in a patient is sensitive to the properties of the incident beam. However, mechanical deformation of the proton therapy facility may occur, and this could be an important factor affecting the proton dose distribution in patients. In this paper, we investigated t...

The superconducting isochronous cyclotron SC200 for proton therapy is under development in Hefei, and the active scanning method has been selected as the beam delivery technology. To reduce energy loss and transverse scattering of the proton beam, a gas chamber in the pencil beam scanning (PBS) nozzle has been designed to shorten the length of the...

We demonstrate a newly developed 3D heat conduction analysis model for YBCO pancake coil by including the turn-to-turn and layer-to-layer heat conduction in the 1-D heat transport equation. The YBCO tape is represented by two thermal components, which are in thermal contact through a thermal resistance. The turn-to-turn and layer-to-layer thermal c...

The quench protection of the close-wound superconducting magnet is a key factor during the design process, especially when used on the particle therapy gantry system. Therefore, the interplay between quench protection and coil quench needs to be considered from the earliest stage of the design. For this purpose, a method using Cryosoft code is pres...

For proton therapy, a beam intensity of 0.4 nA to 4 nA is typically used with a beam transmission factor of 10. However, because of energy degrading, emittance matching, and energy spread selecting, the ratio of beamline transmission (IMax/IMin) for our SC200 proton therapy facility (200 MeV/500 nA) should be far more than 10. Therefore, a novel in...

The purpose of this study is to provide an energy verification method for the nozzle of the SC200 proton therapy facility to ensure safe redundancy of treatment. This paper first introduces the composition of the energy selection system of the SC200 proton therapy facility. Secondly, according to IEC60601 standard, the energy verification requireme...

The purpose of this study is to provide an energy verification method for the nozzle of the SC200 proton therapy facility to ensure safe redundancy of treatment. This paper first introduces the composition of the energy selection system of the SC200 proton therapy facility. Secondly, according to IEC60601 standard, the energy verification requireme...

In cyclotron-based particle therapy facilities, when degrading from maximum to minimum energy use, strong beam loss on degraders and collimators results in a ratio of current up to 10 ³ . Considering patient safety and precision, the beam intensity should vary with energy by a factor of approximately <=10 during fast energy changes. Consequently, t...

The high-temperature superconductor (HTS) (RE)Ba2Cu3Ox (REBCO) conductor on round core (CORC) cable has great advantages with its high current capacity and power density. In REBCO CORC cables, current is redistributed among tapes through terminal contact resistance (TCR) when a local quench occurs. Therefore, its quench behavior is different from t...

The insulation performance of wet wrapping of terminal service box pipework is investigated by the Paschen discharge test in this study. The test mock-up was designed with a U-shaped pipework as the fundamental structure, consisting of insulator breaks, voltage taps, and high voltage wires. In addition, the design of the test mock-up and insulation...

High temperature superconductor (HTS) (RE)Ba2Cu3Ox (REBCO) conductor on round core cable (CORC) has high current carrying capacity for high field magnet and power applications. In REBCO CORC cables, current redistribution occurs among tapes through terminal contact resistances when a local quench occurs. Therefore, the quench behaviour of CORC cabl...

Due to the nonlinear properties of superconductors, modeling of high-temperature superconducting (HTS) devices is difficult, especially for the ones in large scale. In this paper, we develop the multi-scale model from a 2D planar geometry to a 2D axisymmetric geometry to successfully calculate ac loss of large-scale HTS coils. By applying appropria...

The proton beam energy determines the range of particles and thus where the dose is deposited. According to the depth of tumors, an energy degrader is needed to modulate the proton beam energy in proton therapy facilities based on cyclotrons, because the energy of beam extracted from the cyclotron is fixed. The energy loss was simulated for the gra...

The SC200 proton therapy facility is consisting of a supercon-ducting cyclotron, a gantry treatment room and a fixed beam room. The proton beams are transported mainly with beam transport devices, such as dipole magnets, quadrupole magnets and corrector magnets which lie on the beam transport line lay-out of which is based on the beam optics design...

Obtaining distributions of current density, magnetic field, and ac loss in coils is essential for practical applications. However, simulating large-scale 2-generation high-temperature-superconducting, YBCO coils is a challenging task. In this paper, we employ a multiscale model to successfully implement electromagnetic modeling of large-scale YBCO...

The design work of the China Fusion Engineering Test Reactor (CFETR) was started in 2012. Related concept design work for its superconducting magnet system was carried out in the past years. In order to get higher plasma operation parameters, the system was optimized with the major radius ( R ) of 7.2 m, the minor radius ( r ) of 2.2 m, and the p...

At Institute of Plasma Physics of the Chinese Academy of Sciences (ASIPP) a design of the pencil beam scanning (PBS) nozzle is being planned. The main goal of the design is to meet the requirements of radiation field and the scanning speed of the superconducting accelerators SC200, and to achieve a compact structure. Scanning magnets are one of the...

PF4 CFT (Cryostat Feedthrough of No. 4 Poloidal Field Coil) is a key subcomponent of ITER Feeder system. The superconducting busbars of PF4 CFT have insulation protection layer which consists of several half-overlapped pre-preg and glass Kapton for main structure. Base on the special Busbar structure, how to do the electrical tests for production f...

The commercially available high temperature superconductors (HTS) tapes and wires (BSSCO and REBCO) are introduced and the past and present projects to build fusion devices using HTS based magnets are reviewed. The main design options for high current, high field conductors are presented with the related R&D and the open issues. Depending on the ma...

Studies on beam optics and the isocenter property in the gantry system for the SC200 (Superconducting Isochronous Cyclotron of 200 MeV in Hefei, China) are presented in this paper. The physical design of the isocentric gantry system is developed with the software TRANSPORT, which realizes a beam with a circular shape at the isocenter and a full wid...

In order to meet the heating requirement of EAST tokamak, ion cyclotron range of frequency (ICRF) heating is utilized as one of the main auxiliary heating methods, which plays an important role in coupling radio frequency (RF) power into the plasma. As a member of plasma facing components, ICRF antenna suffers the plasma radiation as well which is...

To meet the demands on proton therapy in Russia and China, JINR and ASIPP have started to develop a proton therapy facility based on an isochronous superconducting proton accelerator. A 200 MeV/500 nA proton beam will be extracted from the SC200 superconducting proton cyclotron. Due to the energy of the cyclotron being fixed, an energy selection sy...

The design, field quality optimization, multipole field analysis, and field measurement of a dipole for a newly developed superconducting proton cyclotron (SC200) beamline are presented in this paper. The maximum magnetic field of the dipole is 1.35 T; the bending radius is 1.6 m with a proton beam energy in the range of 70–200 MeV. The magnetic fi...

The concept design of the China Fusion Engineering Test Reactor (CFETR) was started in 2012 in two stages. For CFETR-Phase I, the major radius is 5.7 m, the minor radius is 1.6 m, and the magnetic field at the plasma region, B <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T</sub> , is 4-5 T. There we...

An investigation of induced eddy current effects on the field homogeneity in fast ramped bending magnet was presented in this paper. The transverse field homogeneity and integral field homogeneity were calculated based on 2D/3D finite element analysis. The results showed that the transverse field homogeneity and integral field homogeneity were less...

The Keda Torus eXperiment (KTX) is a new reversed field pinch (RFP) device at the University of Science and Technology of China. The construction and assembly of KTX, including the vacuum chamber, conducting shell, magnetic field windings, power supply system, active control coils, vacuum pump and data acquisition system, have been completed on Aug...

A hybrid superconducting central solenoid employs Bi-2212 high-temperature superconductors and Nb3Sn low-temperature superconductors under the design of the Institute of Plasma Physics, Chinese Academy Of Science for further upgrade to CFETR, namely, the China Fusion Engineering Testing Reactor. The conductor type of both parts is cable-in-conduit...

The operation of superconducting magnet for fusion device is under the complex magnetic field condition, which affect the stabilization of superconductor. The coil-case of TF coil can shield the magnetic field to some extent. The shielding effect is related to the eddy current of coil-case. The shielding effect with different eddy current is studie...

KTX, which stands for “Keda Torus for Experiment”, is a reverse field pinch (RFP) device, with main parameters between RFX and MST. It is supported by China domestic ITER-related research project. The target of KTX is to do the research work of “self-organization”of magnetic confinement plasma. It will include the dynamo and single spiral phenomena...

A new terrella-like device for laboratory simulation of inner magnetosphere plasmas, Dipole Research Experiment, is scheduled to be built at the Harbin Institute of Technology (HIT), China, as a major state scientific research facility for space physics studies. It is designed to provide a ground experimental platform to reproduce the inner magneto...

Nb <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> Sn is considered to be one of the best candidate low-temperature superconducting (LTS) materials for the fusion superconducting magnet system. However, in consideration of the optimization design work of the fusion device magnet system, higher...

An experimental investigation on the critical current ( $I_{c}$ ) degradation of multilayer twisted YBCO tapes in self-field was performed here. The influence of number of tape layers (N) and twist pitch (P) on critical current was researched. The results showed that the influence of helical bending strain and perpendicular self-field on critical c...

The SC200 is a compact superconducting cyclotron, which is designed under the collaboration of ASIPP (Hefei, China)-JINR (Dubna, Russia), for proton therapy. The protons are accelerated to 200 MeV with maximum beam current of ~500 nA. The very high mean magnetic field of 2.9 T-3.5 T (center-extraction) challenges the design of radio frequency (RF)...

According to the agreement between the Institute of Plasma Physics of the Chinese Academy of Sciences (ASIPP) in Hefei, China, and the Joint Institute for Nuclear Research (JINR), in Dubna, Russia, the project of superconducting isochronous cyclotron for proton therapy SC200 is under development at both sites. The cyclotron will provide acceleratio...