at Austin in USA, was dismantled and shipped to China in 2004, and renamed as the Joint TEXT (J-TEXT) tokamak. The reconstruction work, which included reassembly of the machine and development of peripheral devices, was completed in spring of 2007. Consequently, the first plasma was obtained at the end of 2007. At present, a typical J-TEXT Ohmic discharge can produce a plasma with flattop current up to 220kA and lasting for 300ms, line averaged density above 2×10 19 m-3 , and an electron temperature about 800eV, with a toroidal magnetic field of 2.2T. A number of diagnostic devices used to facilitate the routine operation and experimental scenarios were developed on the J-TEXT tokamak. Hence, the measurements of the electrostatic fluctuations in the edge region and conditional analysis of the intermittent burst events near the last closed flux surface (LCFS) were undertaken. The observation and simple analysis of MHD activity and disruption events were also performed. The preliminary experimental results and the future research plan for the J-TEXT are described in detail.

Recent J-TEXT research has highlighted the significance of the role that non-axisymmetric magnetic perturbations, so called three-dimensional (3D) magnetic perturbation (MP) fields, play in a fundamentally 2D concept, i.e. tokamaks. This paper presents the J-TEXT results achieved over the last two years, especially on the impacts of 3D MP fields on magnetohydrodynamic instabilities, plasma disruptions and plasma turbulence transport. On J-TEXT, the resonant MP (RMP) system, capable of providing either a static or a high frequency (up to 8 kHz) rotating RMP field, has been upgraded by adding a new set of 12 in-vessel saddle coils. The shattered pellet injection system was built in J-TEXT in the spring of 2018. The new capabilities advance J-TEXT to be at the forefront of international magnetic fusion facilities, allowing flexible study of 3D effects and disruption mitigation in a tokamak. The fast rotating RMP field has been successfully applied for avoidance of mode locking and the prevention of plasma disruption. A new control strategy, which applies pulsed RMP to the tearing mode only during the accelerating phase region, was proved by nonlinear numerical modelling to be efficient in accelerating mode rotation and even completely suppresses the mode. Remarkably, the rotating tearing mode was completely suppressed by the electrode biasing. The impacts of 3D magnetic topology on the turbulence has been investigated on J-TEXT. It is found that the fluctuations of electron density, electron temperature and plasma potential can be significantly modulated by the island structure, and a larger fluctuation level appears at the X-point of islands. The suppression of runaway electrons during disruptions is essential to the operation of ITER, and it has been reached by utilizing the 3D magnetic perturbations on J-TEXT. This may provide an alternative mechanism of runaway suppression for large-scale tokamaks and ITER.

The J-TEXT tokamak has been operated for 10 years since its first plasma obtained at the end of 2007. The diagnostics development and the main modulation systems, i.e. resonant magnetic perturbation (RMP) systems and the massive gas injection (MGI) systems, will be introduced in this paper. Supported by these efforts, J-TEXT has contributed to research on several topics, especially on the RMP physics and disruption mitigation. Both experimental and theoretical

Abstract.A set of in-vessel saddle coils called dynamic resonant magnetic perturbation (DRMP) for generating rotating resonant magnetic perturbations has recently been constructed on the J-TEXT tokamak. The phenomenon of tearing mode locking to DRMP and rotating together with the DRMP field has been observed.There is an apparent decrease of the island width during the locking and unlocking procedure. Similar results are obtained in the numerical simulation.

Figure 6. a) Synthetic route for the construction of the sp 2 c-COF. Schematic diagrams of b) one-layer and c) multi-layer lattices of sp 2 c-COF. Ball and stick diagrams of d) a 2D sheet with extended π conjugations along the x and y directions and e) the stacked sp 2 c-COF. Reproduced with permission. [21a]