Electronegative Plasma Sheath Structure in a Magnetic Field

The structure of an electronegative plasma sheath in an oblique magnetic field is investigated with a fluid model. We assume the system consists of hot electrons and negative ions as well as cold positive ions. Densities of particles and distributions of the spacious potential in various states of magnetic field are studied. The result shows that the existence of magnetic field and negative ions has great effects on the plasma sheath structures. In addition, the effects of negative ion density and temperature on the structure of the electronegative plasma sheath are discussed.     

The effects of static magnetic field on microwave absorption of hydrogen plasma in carbon nanotubes: A numerical study

We theoretically investigate the microwave absorption properties of hydrogen plasma in iron-catalyzed highpressure disproportionation-grown carbon nanotubes under an external static magnetic field in the frequency range 0.3 GHz to 30 GHz, using the Maxwell equations in conjunction with a general expression for the effective complex permittivity of magnetized plasma known as the Appleton–Hartree formula. The effects of the external static magnetic field intensity and the incident microwave propagation direction on the microwave absorption of hydrogen plasma in CNTs are studied in detail. The numerical results indicate that the microwave absorption properties of hydrogen plasma in iron-catalyzed high-pressure disproportionation-grown carbon nanotubes can be obviously improved when the external static magnetic field is applied to the material. It is found that the specified frequency microwave can be strongly absorbed by the hydrogen plasma in iron-catalyzed high-pressure disproportionation-grown carbon nanotubes over a wide range of incidence angles by adjusting the external magnetic field intensity and the parameters of the hydrogen plasma.     

The effects of a static magnetic field on the microwave absorption of hydrogen plasma in carbon nanotubes： a numerical study

We theoretically investigate the microwave absorption properties of hydrogen plasma in iron-catalyzed high-pressure disproportionation-grown carbon nanotubes under an external static magnetic field in the frequency range 0.3 GHz to 30 GHz, using the Maxwell equations in conjunction with a general expression for the effective complex permittivity of magnetized plasma known as the Appleton-Hartree formula. The effects of the external static magnetic field intensity and the incident microwave propagation direction on the microwave absorption of hydrogen plasma in CNTs are studied in detail. The numerical results indicate that the microwave absorption properties of hydrogen plasma in iron-catalyzed high-pressure disproportionation-grown carbon nanotubes can be obviously improved when the exter- nal static magnetic field is applied to the material. It is found that the specified frequency microwave can be strongly absorbed by the hydrogen plasma in iron-catalyzed high-pressure disproportionation-grown carbon nanotubes over a wide range of incidence angles by adjusting the external magnetic field intensity and the parameters of the hydrogen plasma.     

Current neutralization and plasma polarization for intense ion beams propagating through magnetized background plasmas in a two-dimensional slab approximation

A two-dimensional electromagnetic Particle-in-Cell （PIC） simulation model is proposed to study the propagation of intense, ion beams with beaIn width wb small compared to the electron skin depth c/wpe through background plaslnas in tile presence of external applied magnetic fields. The effcctive eleetron gyrora,dius wge is found to be an important parameter for ion beam transport in the presence of magnetic fields,In the bealn regions, the background plasmas respond differently to the ion beanl of width wb〈wge and wb 〉 wge for the given magnetic field and beaan encrgy, For the case of beam width wb 〈 wge with relative weak external magnetic fiehts, the rotalion effects of plasma electrons a,re found to be signifieant and contributes to the signitica,nt enilaneeinent of the self electric and seif-magnetic fields. While for the ease of beam width wb 〉 wge with relative strong external magnetic fields, the rotation effects of plasma cleetrons are strongly inhibited and a, well neutraliza, tion of ion beam current can be found. Finally, the influences of diftiuent beam widths. beam energies and magnetic fields on the neutralization of ion bc, anl eurrellt are summarized for the eases of wb 〈 wge〈 c/wpe,wge 〈wb〈c/wbp and wb〈c/wpe〈wge.     

Plasma diffusion and transport in a magnetic duct filter

A cathodic arc plasma source equipped with a curved magnetic duct to filter macro-particles was used to study plasma diffusion and transport in the duct. We determine the optimal duct bias, at which the magnetic duct produces the maximum plasma output, for titanium cathodic arc plasma at 50, 100 and 150 A arc current, and we investigate the parametric effects of the arc current and guiding magnetic field on the optimal duct bias. The optimal bias decreases as the guiding magnetic field increases from 0.01 to 0.04T and is almost independent of the guiding magnetic field when the magnetic field strength ranges from 0.04 to 0.06T, the upper limit for our equipment. The optimal duct bias at 0.04T guiding magnetic field decreases with increasing arc current.     

Sheet Plasma Produced by Hollow Cathode Discharge

A sheet plasma is produced by a hollow cathode discharge under an axial magnetic field. The plasma is about40cm in length, 4cm in width and 1 cm in thickness. The electron density is about 10^8cm^-3. The hollow cathodeis made to be shallow with a large opening, which is different from the ordinary deep hollow cathode. A Langmuirprobe is used to detect the plasma. The electron density and the spatial distribution of the plasma change whenvoltage, pressure and the magnetic field vary. A peak and a data fluctuation at about 200 G-300 G are observedin the variation of electron density (or thickness of the sheet plasma) with the magnetic field. Our work will behelpful in characterizing the sheet plasma and will make the production of dense sheet plasma more controllable.     

Thermal Entanglement in the Spin-S Heisenberg XYZ Model

The thermal entanglement in the spin-S Heisenberg XYZ model is studied in detail by using the entanglement measure of negativity. The effects of spin on the thermal entanglement, the threshold temperature, the critical uniform external magnetic field, the nonuniform external magnetic field and the＇, entanglement extremum are discussed, respectively. It is shown that with increasing spin, the entanglement will increase, and then decrease slowly. In addition, we find that entanglement will approach a constant Nc with the increase of DM interaction, the constant increases with the increase of spin, and both the threshold temperature Tc and critical uniform external magnetic field Bc will increase with the increasing spin. Thus high-spin system can inhibit the influence of the external environment better.     

Effects of Adiabatic Dust Charge Fluctuation and Particles Collisions on Dust-Acoustic Solitary Waves in Three-Dimensional Magnetized Dusty Plasmas

Taking into account the combined effects of the external magnetic field, adiabatic dust charge fluctuation and collisions occurring between the charged dust grains and neutral gas particles （dust-neutral collisions）, the dust-acoustic solitary waves in three-dimensional uniform dusty plasmas are investigated analytically. By using the reductive perturbation method, the Korteweg-de Vries （KdV） equation governing the dnst-aconstic solitary waves is obtained. The present analytical results show that only rarefactive solitary waves exist in this system. It is also found that the effects of the wave vector along the z-direction, dust charge variation, collisional frequency, the plasma density, and temperature ratio can significantly influence the characteristics of low-frequency wave modes. Moreover, for the collisional dusty plasmas, there is a certain critical value μc of the plasma density ratio μ, if μ 〈 μc, the width of the waves increases with μ, otherwise the width of waves decreases with μ.     

Generation of Electric Field and Net Charge in Hall Reconnection

Generation of Hall electric field and net charge associated initial conditions of plasma density and magnetic field. with magnetic reconnection is studied under different With inclusion of the Hall effects, decoupling of the electron and ion motions leads to the formation of a narrow layer with strong electric field and large net charge density along the separatrix. The asymmetry of the plasma density or magnetic field or both across the current sheet will largely increase the magnitude of the electric field and net charge. The results indicate that the asymmetry of the magnetic field is more effective in producing larger electric field and charge density. The electric field and net charge are always much larger in the low density or/and high magnetic field side than those in the high density or/and low magnetic field side. Both the electric field and net charge density are linearly dependent on the ratios of the plasma density or the square of the magnetic field across the current sheet. For the case with both initial asymmetries of the magnetic field and density, rather large Hall electric field and charge density are generated.     

Jump Conditions of a Shock with Current in Cylindrical Non-Neutral Plasma

jump conditions of the parameters （mass flow, momentum flow and energy flow） of a shock with current （thereby, electric and magnetic field） in cylindrical non-neutral plasma are presented and derived from Maxwell＇s equations and two fluid equations for electron and ion fluid. The critical Mach number for the shock existence is calculated, which depends on the shock carried current, the ion charge, and the composition of the magnetic and thermal pressure. The numerical results show that both the strength and profiles of the downstream shock parameters will be affected obviously by the shock carried current, electric and magnetic field in the two-dimensional shock.