Since the last IAEA Fusion Energy Conference in 2018, significant progress of the experimental program of HL-2A has been achieved on developing advanced plasma physics, edge localized mode (ELM) control physics and technology. Optimization of plasma confinement has been performed. In particular, high-β _N H-mode plasmas exhibiting an internal transport barrier have been obtained (normalized plasma pressure β _N reached up to 3). Injection of impurity improved the plasma confinement. ELM control using resonance magnetic perturbation or impurity injection has been achieved in a wide parameter regime, including types I and III. In addition, impurity seeding with supersonic molecular beam injection or laser blow-off techniques has been successfully applied to actively control the plasma confinement and instabilities, as well as plasma disruption with the aid of disruption prediction. Disruption prediction algorithms based on deep learning are developed. A prediction accuracy of 96.8% can be reached by assembling a convolutional neural network. Furthermore, transport resulting from a wide variety of phenomena such as energetic particles and magnetic islands has been investigated. In parallel with the HL-2A experiments, the HL-2M mega-ampere class tokamak was commissioned in 2020 with its first plasma. Key features and capabilities of HL-2M are briefly presented.

Summary: Statistical analysis on networks has received growing attention due to demand from various emerging applications. In dynamic networks, one of the key interests is to model the event history of time-stamped interactions among nodes. We model dynamic directed networks via multivariate counting processes. A pseudo partial likelihood approach is exploited to capture the network dependence structure. Asymptotic results are established. Numerical experiments are performed to demonstrate the effectiveness of our proposal.

Net radially inward turbulent particle flux was observed in a linear plasma device, the linear experimental advanced device (LEAD). The amplitude of the inward particle flux is comparable with outward particle flux. The inward particle flux peak value locates in the outer E _r shear layer. Cross-phase evolution dominates the radial evolution of particle flux from outward to inward. In the frequency domain, a 1 kHz mode contributes most of the inward particle flux. Frequency-resolved energy transfer analysis infers that this mode obtains energy nonlinearly from very low frequency fluctuations below 0.5 kHz. Moreover, turbulence spreading could also transfer energy to the position where the inward flux peak locates from nearby positions, and thus acts as a nonlocal, nonlinear drive for the 1 kHz mode.

Based on large energy spread of laser-driven ion beam (LIB), a new method, the Laser-driven Ion-beam Trace Probe (LITP), was suggested recently to diagnose the poloidal magnetic field (Bp) and radial electric field (Er) in toroidal devices. Based on another property of LIB, a wide angular distribution, here we suggested that LITP could be extended to get 2D Bp profile or 1D profile of both poloidal and radial magnetic fields at the same time. In this paper, we show the basic principle, some preliminary simulation results, and experimental preparation to test the basic principle of LITP.