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Effects of three-dimensional (3D) perturbations due to an unstable n = 1 (n is the toroidal mode number) internal kink (IK) on the energetic particles (EPs) are systematically investigated for the HL-2M tokamak, utilizing the MARS-F/K code [Liu et al., Phys. Plasmas 7, 3681–3690 (2000)] and a recently developed test particle tracing module. A high-beta sawteething HL-2M scenario, simulated by the TRANSP code [Breslau et al., Transp Computer Software (2018)], is chosen for this study. In general, the 3D perturbation associated with an unstable IK is found to affect the EP drift orbit, confinement, and loss in HL-2M. The instability-induced EP loss fraction is found to be typically less than 10%, without counting for the prompt orbit loss associated with the 2D equilibrium field for counter-current particles. The latter reaches about 16% in HL-2M. For co-current EPs, a 100 G 3D magnetic field (inside the plasma) due to the IK does not induce any EP loss assuming a static perturbation. A sawtooth-like time-varying perturbation field, with the peak amplitude reaching 1000 G, can however produce about 30% loss for the co-current EPs in HL-2M. The majority of lost EPs tend to strike the lower divertor region, with a small fraction of particles striking the low-field side mid-plane region of the limiting surface. [ABSTRACT FROM AUTHOR]

A systematic investigation is carried out, studying the effect of the neutral beam injection induced energetic particles (EPs) on the n = 1 (n is the toroidal mode number) internal kink (IK) instability in the HL-2M tokamak, utilizing the MARS-F/K code [Liu et al., Phys. Plasmas 7, 3681 (2000) and 15, 112503 (2008)]. A high-beta sawteething HL-2M scenario, simulated by the TRANSP code [Breslau et al. Computer Software (2018)], is chosen for this study. Compared to the fluid model, non-perturbative magnetohydrodynamic (MHD)-kinetic hybrid computations with MARS-K show a generally stabilization effect on the IK, due to drift kinetic resonances associated with EPs. The bounce resonance of trapped EPs has minor influence on the mode stability. In the absence of the plasma equilibrium flow and with the assumed particle pitch distribution, the transit resonance of co-current (countercurrent) passing EPs destabilizes (stabilizes) the IK. With plasma flow, both co- and countercurrent passing EPs tend to stabilize the mode, but the effect is stronger with the countercurrent particles. These modeling results provide useful guidance for interpreting MHD instabilities in the future high-performance experiments in HL-2M. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the efficacy of using additional locking plate-derived Poller screws to treat post-intramedullary nailing for femoral non-union was investigated. Methods: Between January 2009 and April 2012, six patients who underwent post-intramedullary nailing for femoral non-union were studied. Three, one, and two patients had femoral fractures in the proximal one-third, middle third and distal third, respectively. While the original intramedullary nails were retained, eight-to-nine hole locking plates were used for fixation and two-to-three cortical bone screws were applied to both sides of the fracture to ensure the stability of the intramedullary nail sagittal plane. One-to-two pieces of locking nails were inserted tightly next to the intramedullary nails to ensure a stable coronal plane. Autologous iliac bone grafts were performed around the fractures in all cases. Results: Follow-up evaluations were conducted between 10 and 17 months (mean, 13.8 months). The operative time was 110-160 minutes and the blood loss was 300-500 mL. Bone pain was relieved in 1 month. Continuous callus was observed after 4-6 months (mean, 4.83 months) based on imaging. There were no infections, loosening of internal fixation, or rupture. All patients were able to walk bearing weight within 3 months. Conclusion: An additional locking plate and the derived Poller screw technique effectively improved local rotation instability and is an effective and simple treatment method for femoral non-union after intramedullary nailing. [ABSTRACT FROM AUTHOR]