Experimental observation of the electron beam focusing effect induced by plasma currents with opposite directions.

We report on the experimental observation of the focusing effect of a 50MeV accelerator electron beam in a gas-discharge plasma target. The plasma is generated by igniting an electric discharge in two collinear quartz tubes, with the currents up to 1.5kA flowing in opposite directions in either of the two tubes.

Permeability enhancement of the KcsA channel under radiation of a terahertz wave.

Potassium ion channels are essential elements in cellular electrical excitability and help maintain a resting potential in nonexcitable cells. Their universality is based on a unique combination of strong selectivity for K^{+} ions and near-diffusion-limited permeation efficiency. Understanding how the channel regulates the ion conduction would be instructive to the treatment of ion channelopathies.

Enhanced collective stopping and drift of electron beams in fusion plasmas with heavy-ion species.

The transport and energy deposition of relativistic electron beams in transversely nonuniform plasmas are investigated with two-dimensional electromagnetic particle-in-cell simulations. For the beam with radius much larger than plasma skin depth, the current filamentation instability excited by the electron beam can be observed, which breaks the beam into filaments and leads to the formation of strong magnetic fields consequently. The effects of plasma ion species are significant and asymmetric transverse magnetic fields are formed in plasmas with heavy-ion species due to the asymmetric neutralization of beam space charge by plasma ions.

Time evolution and energy deposition for ion clusters injected into magnetized two-component plasmas.

A two-dimensional particle-in-cell simulation model is proposed to study the time evolution and energy deposition for ion clusters injected into magnetized two-component plasmas. The injection of an isolated ion cluster is studied in the case of weak and strong magnetic fields. For strong magnetic fields, the ions tend to deposit their energy smoothly along the trajectory of the cluster, due to the confinement by the strong magnetic fields.

Wake effect and stopping power for a charged ion moving in magnetized two-component plasmas: two-dimensional particle-in-cell simulation.

A two-dimensional particle-in-cell (PIC) model is proposed to study the wake field and stopping power induced by a nonrelativistic charged particle moving perpendicular to the external magnetic field in two-component plasmas. The effects of the magnetic field on the wake potential and the stopping due to the polarization of both the plasma ions and electrons are discussed. The velocity fields of plasma ions and electrons are investigated, respectively, in the weak and strong magnetic field cases.

Dynamic polarization and energy dissipation for charged particles moving in magnetized two-component plasmas.

Energy losses of test particles in magnetized two-component plasmas are investigated within the framework of the linearized Vlasov-Poisson theory, taking into account the dynamic polarization effects of both the plasma ions and electrons. General expressions of the potential and stopping power are obtained and calculations are performed for protons in a magnetized hydrogen plasma. The influences of the magnetic field, the angle between the proton velocity and magnetic field, and certain plasma parameters on the stopping power are studied.