Abstracts:Profiles of power deposition on the first wall of the Joint European Torus (JET) tokamak experiment are fit by tracing an analytic representation for the distribution of power from midplane along lines of magnetic field. The technique is used to help design plasma-facing components (PFCs) in reactor-scale magnetic confinement devices; hence, understanding how to employ it both efficiently and accurately is important. Focusing on JET divertor geometry, the work examines the sensitivity of the integrated power and maximum power per PFC tile to the representation of the magnetic field and to the discretization of the tile’s own geometry and that of other PFCs. For design, it is helpful to reduce computation costs per realization to a few seconds of elapsed time, and the work concludes with recommendations and guidelines for minimizing cost while retaining adequate accuracy.

Abstracts:In the process of sliding electrical contact, the current would cluster locally under the effect of velocity skin effect (VSE) and complex damage on the contact interface would occur under the coupling effect of Joule heat, frictional heat, and high-speed impact, which would seriously affect the safety and stability of sliding electrical contact systems. In this article, a modified smoothed particle hydrodynamics (SPHs) method is introduced into the study of the damage to the sliding electrical contact interface while considering the VSE in the process of sliding electrical contact. First, the magnetic induction equation is introduced into the SPH method. Then, the distribution characteristics of multiple physical fields are simulated, and the effects of velocity while considering the VSE are analyzed. Furthermore, considering the nonuniform distribution of current caused by the VSE, the effects of the vertical velocity of the slider on the characteristics of gouge damage are studied. The results show that in the process of sliding electrical contact, the magnetic field and current would gather on the sliding electrical contact interface and thus lead to a concentrated temperature rise at the end of the slider. Additionally, the greater the velocity of the slider, the more obvious the VSE becomes. The results also show that the vertical velocity plays a vital role in the morphology of gouge crater. When the vertical velocity is relatively high, a new gouge crater may appear based on the original damage. The critical vertical velocity that would induce gouge damage is also discussed in this article.

Abstracts:In this work, we prove that the cumulation (self-focusing) of charged particles in a plasma (with current) is a universal property of cumulative-dissipative structures with characteristic sizes from $10^{-15}$ to $10^{27}$ m. In this work, we theoretically (Part 1) and experimentally (Part 2) prove that shock waves of electric fields are focusing shells for plasma cumulative-dissipative positively charged plasma 3-D structures. In Part 1 of this work, we provide detailed theoretical justifications for the possibility of the existence of (locally self-focusing by ambipolar drift) Vysikaylo’s electric field shock waves caused by ambipolar diffusion due to a violation of the electrical neutrality of the plasma (in the presence of an electric current). Due to the greater mobility of electrons (ions are more massive), a structure with a positive space charge is formed in the electric field shock waves that self-form in the plasma (with current). Unlike Mach’s shock waves, in closed Vysikaylo’s shock waves transverse electric fields are generated due to space charge. This makes the problem (in the shock wave region of the electric field) 3-D (in particular, spherically symmetric in this region). In Part 1, we will limit ourselves to the study of stationary 1-D profiles: 1) parameters in shock waves of the electric field and 2) processes of ambipolar drift, leading to local cumulation of positive charge in the shock wave of the electric field. In Part 1, the author will limit himself to obvious remarks arising from the properties of 3-D structures with a positive space charge. Based on laboratory 3-D experiments (Part 2) and theoretical studies of gas-discharge plasma, we prove that ambipolar drift caused by different dependences of the mobility of electrons and positive ions in a simple plasma (with one type of ions) determines the dynamic processes of cumulation of plasma structures—4-D plasmoids in plasma (with current). Four-dimensional plasma structures are nonstationary 3-D structures. The author draws attention to self-formation in plasma structures (plasmoids) of stationary Vysikaylo’s plasma nozzles—analogs of Laval’s nozzles. A comparison of theoretical 1-D and experimental 3-D observations of discharge glow (this corresponds to changes in the main parameters) in gas discharge tubes will be presented in Part 2. In these experiments, a homogeneous plasma in a gas discharge tube is locally disturbed by a beam of fast electrons. This leads to the self-formation: 1) of electric field shock waves (a layer of positive volume charge) stopped by gas pumping and 2) of transition 3-D profiles and Vysikaylo’s plasma 3-D nozzles already in a quasi-neutral homogeneous plasma.

Abstracts:Plasma generated by a submerged arc has great potential in wastewater treatment. Carbon is widespread in nature. It is easily acquired and biocompatible. In this article, a low-voltage submerged arc generated by contact-separate of two electrodes is proposed to decompose methylene blue (MB). The process achieved a removal efficiency of 92.9% after 15 min treatment. The emission spectrum of the submerged arc indicated that active particles such as $\cdot $ OH radicals, oxygen atoms, and hydrogen peroxide (H2O2) have been produced. Additionally, in the process of arc treatment, the wavelength of the absorption peak of MB solution shifted toward ultraviolet region. It indicated the demethylation of the MB molecules. The eroded particles from the graphite electrodes were also examined, and the carbon quantum dots were observed. Furthermore, micro-scale fibrous entangled particles and layered particles with abundant pore structures were observed. These results demonstrate that the eroded particles own an absorption ability for MB, continuing decolorization of the treated solution without additional active particles generated by the submerged arc plasma.

Abstracts:In this article, a kind of armature ablation calculation method is presented considering mechanical (high-speed friction transformation, friction) and magnetohydrodynamic and so on. The main features of this approach simplify the armature material solid-build-gas phase transformation model, high-speed friction, and wear model and the contact surface magnetohydrodynamic film model. The new standard to the armature ablation is that not only the element material melting point temperature is reached but also has a minimum plastic strain; at this moment, this element is recognized as dissolution. Finally, the simulation results are compared with the experimental results; both are in good agreement, so as to verify the correctness of this algorithm.

Abstracts:As frequency resources become increasingly scarce, the need to develop miniaturized, dual-band filters for improving spectrum utilization in broadband communications have become urgent. In this article, we introduce a novel approach for designing a dual-band bandpass filter (BPF) using a hybrid technique that combines substrate-integrated waveguide (SIW), spoof surface plasmon polariton (SSPP), and complementary split ring resonator (CSRR) technologies. The substrate-integrated plasmonic waveguide (SIPW) is created by etching meander-slot SSPP structures onto the top layer of the SIW. This design reduces both the lateral and longitudinal dimensions without adding complexity. By etching CSRRs onto the back of the SIW, the filter achieves strong electromagnetic coupling and narrowband suppression, resulting in a dual-band BPF with operating frequencies of 7–8.1 and 10–11.2 GHz. To validate this design, we fabricated and measured a prototype. The results demonstrate that the proposed SIPW BPF exhibits exceptional filtering performance, with a return coefficient of more than −10 dB and an insertion loss (IL) of less than 1.7 dB in both passbands. In adddition, the designed BPF features wide passband and stopband characteristics.