In this paper, a two-dimensional axisymmetric particle-in-cell plus Monte Carlo collision numerical model is developed to simulate the plasma and electromagnetic characteristics inside the discharge chamber of an ion thruster. This model tracks three major particle types: primary electrons, secondary electrons, and xenon ions. The neutral particles are treated as a background gas, and the collision mechanism between electrons and neutral gas is modeled in detail. Besides the external electric field and magnetic field, the time-varying electromagnetic fields caused by the movement of the charged particles are considered. Compared to the electrostatic model, the electromagnetic model can further study the electromagnetic radiation characteristics of the discharge chamber. The numerical results are presented and discussed, including the particle number density distributions, the particle energy distributions, and the time-varying electromagnetic fields. At last, the influence of the electromagnetic effect on ion dynamics is analyzed.

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Strong adhesives as structural load-bearing materials can provide both adhesive bonding to substrate surfaces and cohesive bonding throughout the bulk material, which are widely used in the cement nail, electronic device, and automotive industries. By a molecular topological regulation, in this work, we developed a series of strong adhesives based on comb-like polymers. By systematically regulating the topological parameters including the side chain length, the spacer between side chains, and the degree of polymerization of the overall backbone, comprehensive studies on linear rheology (the terminal relaxation time and zero viscosity) and non-linear debonding adhesion (the work of adhesion) are performed on these comb-like polymers. It was found that the rheological behaviors depend not only on the structure parameters but also on whether or not the samples exhibit phase separation. Moreover, regardless of the topological structure of comb-like polymers with strong and weak phase separation, the universal work of adhesion is observed to be dependent on the multiplication of terminal relaxation time and the debonding rate, indicating dynamic control over the nonlinear work of adhesion. Furthermore, comb-like polymers are feasible to bind with diverse substrates, including glass, polypropylene and polyethylene terephthalate, wood, and metal. In comparison to existing works using dynamic physical or chemical bonds, molecular topology regulation is more easily fulfilled in strong adhesives without the use of additives and complicated chemical and physical modifications, lowering the barrier for practical applications.