• <tr id="yyy80"></tr>
  • <sup id="yyy80"></sup>
  • <tfoot id="yyy80"><noscript id="yyy80"></noscript></tfoot>
  • 99热精品在线国产_美女午夜性视频免费_国产精品国产高清国产av_av欧美777_自拍偷自拍亚洲精品老妇_亚洲熟女精品中文字幕_www日本黄色视频网_国产精品野战在线观看 ?

    3D fluid model analysis on the generation of negative hydrogen ions for negative ion source of NBI

    2023-11-16 05:38:10SiyuXING邢思雨FeiGAO高飛YuruZHANG張鈺如YingjieWANG王英杰GuangjiuLEI雷光玖andYounianWANG王友年
    Plasma Science and Technology 2023年10期
    關(guān)鍵詞:王友英杰

    Siyu XING(邢思雨),Fei GAO(高飛),?,Yuru ZHANG(張鈺如),Yingjie WANG(王英杰), Guangjiu LEI (雷光玖) and Younian WANG (王友年)

    1 Key Laboratory of Materials Modification by Laser, Ion, and Electron Beams (Ministry of Education),School of Physics, Dalian University of Technology, Dalian 116024, People’s Republic of China

    2 Southwestern Institute of Physics, Chengdu 610225, People’s Republic of China

    Abstract

    Keywords: negative hydrogen ion sources, China Fusion Engineering Test Reactor, threedimensional fluid model

    1.Introduction

    The raw materials for nuclear fusion are isotopes of hydrogen,i.e.deuterium and tritium, which have the largest reaction cross section and can release huge amounts of energy.Since ohmic heating cannot alone attain the temperature required for fusion, various auxiliary heating mechanisms, such as NBI(neutral beam injector)heating,are needed to heat the plasma to its ignition temperature [1].Obtaining an energetic neutral beam is important in an NBI system.At energies above 100 eV amu?1,the neutralization efficiency of positive ions is not sufficient [2, 3] and an RF NHIS (radio-frequency negative hydrogen ion source) has been adopted at the CFETR(China Fusion Engineering Test Reactor)to generate negative ion beams.

    Over the past few years, significant progress has been achieved in the global modeling of RF NHIS[4-8].Gaboriau and Boeuf systematically investigated the evolutions of the particle density and temperature with power and pressure,and gas depletion was taken into account by resolving the H heating equation[4].Huh et al studied the density of H?and other species under different electron energy distributions,and they observed that the plasma properties exhibited good agreement with experimental measurements when employing a bi-Maxwellian distribution[5].Yang et al presented a fairly comprehensive benchmark to validate the Global Model for Negative Hydrogen Ion Sources [6] and then developed a reduced linear model that could perform the VDF(vibrational distribution function) with high computational efficiency [7].Recently,Zhang et al grouped the vibrationally excited states of hydrogen molecules in order to simplify the chemical reaction set and concluded that this strategy could greatly reduce the computational cost of producing highly accurate estimates of negative hydrogen ion density [8].

    Since the spatial distributions of plasma properties are very important for a deeper understanding of an NHIS, fluid models are also necessary.Paunska et al employed 1D (onedimensional)and 2D(two-dimensional)fluid models to study the density distributions of charged particles and vibrational molecules in hydrogen discharges, and they found that when the radius of the reactor was small,negative ions accumulated considerably in the discharge center [9, 10].Hagelaar et al analyzed the evolution of the plasma parameters with discharge conditions by combining a 2D fluid model with an electromagnetic field solver and their results showed that the neutral gas temperature varied with power and pressure [11].By enriching the chemical processes involved, Boeuf et al revealed that plasma density gradually saturated as power increased [12].Subsequently, Boeuf et al compared the electron temperature obtained in cases with and without a magnetic filter and concluded that the introduction of a magnetic filter reduced the electron density and temperature in the expansion region [13, 14].In addition, Lishev et al pointed out that the magnetic field penetrating through the driver volume became stronger if the magnetic filter was moved upwards and away from the expansion region,and this resulted in significant plasma asymmetry[15,16].Wang et al employed a 3D (three-dimensional) fluid model to simulate hydrogen discharges in a reactor with a cylindrical driver region and a rectangular expansion region, and the effects of magnetic filter,pressure,power and magnetic shielding on the plasma properties were studied [17].

    Despite the NHIS being examined through various models, there remain certain inadequacies that need to be addressed.In a single-driver NHIS prototype, the plasma is generated in a cylindrical driver region and then diffuses into a rectangular expansion region.In addition, a magnetic filter,which causes substantial asymmetry, is included in the expansion chamber.In this two-chamber structure, a 3D model is required to describe the discharge characteristics more accurately.However, due to the computational burden,multi-dimensional simulations of the NHIS are limited.In addition, the chemistry set is usually simplified in the fluid model and the H?ion reactions are usually excluded [17].Since the generation of H?ions is one of the key issues in an NHIS, it is necessary to establish a multi-dimensional fluid model with H?ions taken into account in a self-consistent manner.Therefore, to study the properties of an RF NHIS, a 3D fluid model has been described by using COMSOL(COMSOL Multiphysics) that includes the self-consistent calculation of H?ions based on the lumped-levels method[8].Given the high powers and low pressures at which an NHIS operates, this work incorporates ion mobility under a high field and the effective electron collision frequency to address these factors.In addition, due to the presence of the magnetic filter, the electron transport coefficients and plasma conductivity are in full tensor form.

    Figure 1.Schematic diagram of the RF NHIS.

    2.Model description

    Figure 1 shows the schematic diagram of the two-chamber RF NHIS used in this work.The small cylindrical chamber at the top,with an inner diameter of 28 cm and a height of 14 cm,is the driver region, which is externally wound with a five-turn coil.A 2 MHz RF power source is applied to the coil and then a time-varying azimuthal electric field is generated to partially ionize the working gas (H2) and maintain the discharge.The larger rectangular chamber in the lower part is the expansion region,with a length of 60 cm,a width of 50 cm and a height of 25 cm.Ten permanent magnets magnetized to a remanence of 2.1 T are arranged symmetrically along the x-direction on the side walls of the expansion region at 2 cm intervals to generate magnetic filter field in the ?y-direction inside the chamber.The length, width and height of each permanent magnet are 9 cm, 5 cm and 2 cm respectively.The 3D fluid model is established within COMSOL and it includes fluid,plasma chemistry, electromagnetic field and static magnetic field modules, which are described in detail below.In the simulation, tetrahedral meshes are used.The minimum and maximum mesh sizes in the plasma region are 0.1 cm and 3 cm.To increase stability and calculation accuracy, several dozen boundary layers with thicknesses of less than 0.1 cm are adopted at the boundaries.

    2.1.Fluid module

    Although the temperature gradient, inertial term, nonlinear convection term and nonlinear Lorentz force term become obvious at high power and low frequency, the focus of this paper is on the self-consistent simulation of the H?ion generation by using a 3D fluid approach.In order to achieve fast 3D simulations,the above effects are temporarily ignored and the drift-diffusion equation is used for charged particles [33].

    2.1.1.Electrons.For electrons, we solve the electron continuity and energy balance equations

    whereneandare the electron and electron energy densities, respectively, andTerepresents the electron temperature.eΓ and Γεare the electron flux and electron energy flux,E is the electrostatic field, andPindis the inductive power deposition (see section 2.3 below).Rerepresents the electron generation and loss, andRεis the energy source term induced by inelastic collisions

    wherenaandnbare the reactant number density,andεjis the threshold energy for reactionj.The rate coefficientkjfor reactionjis obtained according to the cross sectionσj

    whereγis the coefficient,εeis the electron energy andfis the electron energy distribution function,which is assumed to be a Maxwellian distribution in this work.

    In the simulation, the initial parameters are chosen to have values that could help to reach convergence over a shorter computational time.The initial densities for electrons,positive and negative ions are set to be 1×1017m?3,3.3×1016m?3and 1×1015m?3,respectively,the initial electron energy is 5 eV,and the initial molar fraction of various neutral particles is 1 × 10?2.

    2.1.2.Heavy particles.The transport of heavy particles, i.e.ions and neutrals, is described by the multicomponent equations:

    wheremkis the ion mass,Nnis the neutral number density andkσis the cross section of the reaction between ions and neutrals.The ion-diffusion coefficientDkis calculated according to Einstein’s relation.The diffusion coefficient of a neutral particle is

    whereDkjis the binary diffusion coefficient between specieskandj, andxjis the mole fraction for speciesj.

    2.1.3.Boundary conditions.By ignoring the drift effect,secondary electron emission and thermal emission, the boundary conditions for electron flux and electron energy flow are

    whereMkandckare the molar mass and molar concentration for species k.Note that the second term is only taken into account for ions.

    2.2.Plasma chemistry

    In this work, 23 species are considered, including electrons,H?, H+, H2+, H3+, hydrogen molecules and atoms in the ground state, H(n = 2) and H(n = 3) atoms in the excitedstate, and 14 hydrogen molecules in the vibrationally excited state (v= 1-14).These species collide with each other and the reactions are listed in table 1.

    Table 1.Reactions included in this work.

    In an NHIS, negative hydrogen ions H?are mainly produced by dissociative attachment (DA) reactions between low-energy electrons and vibrationally excited hydrogen molecules H2(v= 1-14).They are mainly lost through electron detachment (ED), mutual neutralization (MN) and associative detachment (AD) (see table 1).In order to reduce computational cost, the level-lumping method (i.e.grouping the vibrationally excited hydrogen levels) is adopted to simplify the chemistry set[34].According to the calculated VDF,the 14 vibrational levels are divided into three groups:v=1-4 is group 1(w=1),v= 5-9 is group 2(w=2)andv= 10-14 is group 3 (w = 3).Then, the reactions of the 14 vibrationally excited levels H2(v=1-14)are replaced by the reactions of the three groups, i.e.H2(w = 1-3).The number density for each group is calculated by the redefined particlebalance equation and the corresponding reaction rate coefficients are determined according to the internal partition function of these groups [8].The grouping method used in this work can not only accurately reproduce the plasma characteristics, but also reduce the number of equations to be solved in the model.Note that although H2(v= 1-14) are combined into four groups in [8], under the discharge conditions of this work,the three-group model can reproduce the plasma properties accurately, as will be illustrated in section 3.1 below.

    2.3.Electromagnetic field module

    The electromagnetic field is described by Maxwell’s equations.By introducing the magnetic vector potential and considering the harmonic approximation (A = A1eiωt),Maxwell’s equations yield

    where A1is the amplitude value,iis the imaginary unit,ωis the angular frequency,εis the dielectric constant,is the unit tensor,Jcoilis the coil current density andμis the magnetic permeability.The plasma conductivityis expressed as

    Figure 2.Distributions of the negative hydrogen ion density (a), electron density (b) and electron temperature (c) along the axial direction obtained by the models when the vibrationally excited molecules H2(v =1-14)are grouped(solid line)and considered individually(dashed line) at different pressures.

    Since the NHIS works at low pressure,i.e.,0.3-2 Pa,stochastic heating, not ohmic heating, has a dominant influence.Therefore,the effective collision frequencyνeffis adopted,wherevenis the elastic collision frequency between electrons and neutral particles, andvstocis the stochastic heating frequency

    here,δeffis abnormal skin depth

    The inductive power deposition is

    where the plasma current density can be written as

    The electrostatic field is obtained by solving Poisson’s equation

    whereρVis the charge density and0εis the vacuum permittivity.Since the bottom and side walls of the chamber are grounded, the boundary conditions for the electric potential isV=0.

    2.4.Magnetostatic module

    In the magnetostatic module, the magnetic field intensity is equal to the negative gradient of the magnetic scalar potentialVm

    whereM is the magnetization intensity andμ0is the vacuum permeability.According to the magnetic insulation, we have= 0at the boundaries.

    3.Results and discussion

    In this work, negative hydrogen ion distributions are selfconsistently calculated by using a 3D fluid model at high power (40 kW), low pressure (0.3-2 Pa) and different magnetic filter positions(z=25,19,13 cm).In this model,the ion and neutral gas temperatures are assumed to be 600 K [16].First, the validity of the level-lumping method for the calculation of the NHIS is confirmed.Then, the evolution of negative hydrogen ion density in the x-z and x-y planes with pressure and magnetic filter position are presented,which can be understood on the basis of local (collisions) and non-local(transport) contributions.

    3.1.Validity of the level-lumping method

    In order to illustrate the validity of the level-lumping method,we have compared the plasma properties obtained when the vibrationally excited molecules H2(v= 1-14) are grouped and when they are considered individually by using a 2D axisymmetric model, in which the expansion region is assumed to be cylindrical with a radius of 25 cm.It can be seen from figure 2(a) that when the pressure is 0.3 Pa and 0.6 Pa, the axial distributions of the negative hydrogen ion density obtained with the level-lumping method agree well with those obtained when H2(v= 1-14) are treated individually.As the pressure increases to 1 Pa and 2 Pa, there is a slight difference in absolute values.This is because the deviation of the VDF obtained by the group model from that of the individual-levels model becomes obvious as pressure increases,especially for the second group(i.e.H2(v=5-9)),which contributes the most to the generation of negative hydrogen ions (see figure 3 below).In addition, the levellumping strategy barely affects the electron properties, which is clear from the electron density and electron temperature in figures 2(b)and(c).Therefore,we can conclude that applying the level-lumping method in the fluid model is feasible,which could help to simulate an NHIS accurately with a low computational cost.

    Figure 3.Distributions of the production rate of negative hydrogen ions yielded by different vibrationally excited groups H2 (w = 1-3)along the z-direction(x=30 cm,y=25 cm).The pressure is 0.6 Pa and the power is 40 kW.

    In order to detect the influence of each group of vibrationally excited states H2(w = 1-3) on the generation of negative hydrogen ions, calculations are performed in the geometry of figure 1 and the production rate is plotted in figure 3.It can be clearly seen that the second group plays a dominant role and that the production rate is three times higher than that of the third group and even more than two orders of magnitude higher than the first group.Therefore,only the density distribution of the second group of vibrationally excited states (i.e.H2(w = 2)) is presented in the following discussion.

    3.2.Effect of pressure

    3.2.1.x-z plane.Figure 4 shows the spatial distributions of the negative hydrogen ion density at various pressures in the x-z plane(y=25 cm),with the power fixed at 40 kW and the magnetic filter located at the bottom of the expansion region(z=25 cm).It is clear that the negative hydrogen ion density has an asymmetric distribution at all of the investigated pressures due to the existence of the magnetic field.As the pressure increases, the peak of the negative hydrogen ion density moves horizontally along the x-direction(i.e.from the left of the symmetric axis to the right), with the maximum value rising monotonically.This is because both the electron density and H2(w = 1-3) density increase with pressure.Meanwhile, the electron temperature becomes lower, giving rise to enhanced H?generation.Note that the symmetric axis of the reactor is placed at x=30 cm,and‘left’(region where x<30 cm) and ‘right’ (region where x>30 cm) are absolutely determined.

    In order to explain the evolution of the H?density with pressure in more detail, it is necessary to analyze the local(collisions) and non-local (transport) processes of negative hydrogen ions.The reactant density and the rate coefficient determine the source term through collisions,and the electric field determines the transport direction and coefficient.Asymmetric electron density, electron energy and potential distributions are formed because electrons are deflected by E×B drift and diamagnetic drift [16, 17], resulting in asymmetric collisions and transport (see below).

    Figure 4.Spatial distributions of the negative hydrogen ion density in the x-z plane (y = 25 cm) at different pressures.

    The color scale in the first row of figure 5 shows the source term of negative hydrogen ions RH?through collisions at different pressures, i.e.local process.The black and white contour lines represent the production rate (reaction 18) and destruction rate (reactions 20, 21, 22 and 23).Since the negative hydrogen ions are mainly generated by the second group of the vibrationally excited hydrogen molecules, H2(w =2) density is plotted in the second row.As the pressure increases, the maximum H2(w = 2) density becomes higher and moves closer to the left wall of the driver region.A second peak of H2(w = 2) density also appears at the right wall at 2 Pa (figure 5(h)) due to the increasing electron temperature there (not shown here) [17].

    When the pressure is 0.3 Pa, the maximum production rate(black contour lines)appears at the right-hand side of the expansion chamber and gradually moves upwards to the left wall of the driver region as pressure increases.In the presence of a magnetic filter at 0.3 Pa,the E×B drift and diamagnetic drift result in an asymmetric distribution of electron temperature, i.e.the maximum electron temperature appears on the left-hand side of the wall [16, 17].Since negative hydrogen ions are mainly generated by low-energy electrons,production on the right-hand side is more pronounced.When the pressure becomes higher, on one hand, the electron temperature decreases and the asymmetry becomes less obvious.On the other hand, the density of reactants (i.e.electrons and vibrationally excited states) on the left-hand side of the driver region is higher and the discrepancy between the driver and expansion regions is more obvious[17], which is clear from the H2(w = 2) density.Moreover,the destruction rate in most areas of the driver region is greater than the production rate, leading to a negative source term.In contrast,the source term is greater than 0 in the lower part of the expansion region.

    Figure 5.The source term of negative hydrogen ions(first row)and H2(w=2)density(second row)in the x-z plane(y=25 cm)at different pressures.The black and white contour lines in the first row represent the production and destruction rates of negative hydrogen ions.

    Figure 6.The flux of negative hydrogen ions(first row)and plasma potential(second row)in the x-z plane(y=25 cm)at different pressures.The arrows in the first row represent the direction of flux.

    The negative hydrogen ion density is not only affected by collisions, but also by transport, i.e.non-local processes.Therefore, the negative hydrogen ion flux ΓH?at different pressures are plotted in the first row of figure 6, where the arrows represent the direction of flux.The transport of ions is determined by both the drift caused by the electric field and the diffusion due to the density gradient.Within the studied discharge conditions in this work, since the diffusion flux is two orders of magnitude lower than the drift flux, ΓH?is mainly affected by the drift process.It can be seen from the second row of figure 6 that the maximum plasma potential appears on the left-hand side of the driver region, which is again caused by the movement of electrons due to E×B drift,and it drops sharply at the vessel wall, creating a strong electric field.Under this electric field force,although negative hydrogen ions are mainly generated on the right-hand side of the expansion chamber, the maximum density appears on the left (see figure 4(a) above).When the pressure increases, the plasma potential becomes lower,but with better homogeneity.Therefore,the negative hydrogen ion flux is directed from the wall towards the region with maximum plasma potential.

    As a result, although negative hydrogen ions are mainly produced at the bottom of the expansion region, they drift upwards under the electric field force, with the maximum appearing at the junction of the driver and expansion regions.In the horizontal direction, maximum H?takes place on the left-hand side of the symmetric axis at 0.3 Pa,and it moves to the right-hand side at 2 Pa,indicating that transport dominates the H?density distribution at low pressures and collisions have a greater influence at high pressures.

    Figure 7.Distributions of negative hydrogen ion density in the x-y plane (z = 20 cm) at different pressures.

    3.2.2.x-y plane.Figure 7 shows the distribution of H?density in the x-y plane (z = 20 cm), calculated under the same discharge conditions as figure 4.It can be seen that the negative hydrogen ion density increases and then decreases with pressure, and the maximum moves from the right-hand side of the symmetric axis to the left.

    Figure 8.The source term of negative hydrogen ions(first row)and H2(w=2)density(second row)in the x-y plane(z=20 cm)at different pressures.The black and white contour lines in the first row represent the production and destruction rates of negative hydrogen ions.

    Figure 9.The flux of negative hydrogen ions(first row)and plasma potential(second row)in the x-y plane(z=20 cm)at different pressures.The arrows in the first row represent the direction of flux.

    Figure 10.The magnetic field intensity at different magnetic filter positions.

    Figure 11.Distributions of negative hydrogen ion density in the x-z plane (y = 25 cm) without and with a magnetic filter placed at different positions.

    The source term of negative hydrogen ions RH?at different pressures in the x-y plane is shown in the first row of figure 8.At all pressures investigated in this work, the production rate of negative hydrogen ions is greater than the destruction rate, giving rise to the positive source term.At 0.3 Pa, the source term on the right-hand side of the symmetric axis is larger than on the left, due to the lower electron temperature there.As pressure increases,the value at the left-hand side gradually exceeds that at the right due to less asymmetry in the electron temperature and the higher reactant density (i.e.electron and H2(w = 2) density) on the left-hand side, which can be seen in the second row of figure 8.Indeed,the reactant density plays a dominant role in the H?production rate at high pressures, due to the greater symmetric energy flow deposition.The H2(w = 2) density exhibits two maxima at 2 Pa (figure 8(h)) because the diffusion becomes less important and the discharge is more local at high pressure.

    Figure 12.The source term of the negative hydrogen ions (first row) and H2 (w = 2) density (second row) in the x-z plane (y = 25 cm)without and with magnetic filter placed at different positions.The black and white contour lines in the first row represent the production and destruction rates of negative hydrogen ions.

    Figure 13.The flux of negative hydrogen ions(first row)and plasma potential(second row)in the x-z plane(y=25 cm)without and with a magnetic filter placed at different positions.The arrows in the first row represent the direction of flux.

    The first row of figure 9 shows the absolute value and direction of the negative hydrogen ion flux ΓH?at different pressures in the x-y plane.Again, the drift flux plays a dominant role,i.e.the value is one order of magnitude higher than the diffusion flux.Again,ΓH?in the x-y plane is directed from the vessel wall to the position with maximum plasma potential (the second row of figure 9).As the pressure increases, the flux first increases and then decreases.This is because although more negative ions are generated at high pressure, the transport along the z-axis is suppressed.Moreover, the maximum of the negative hydrogen ion density appears on the right-hand side at 0.3 Pa, indicating that the transport effect at the bottom of the expansion region is much weaker than the collisions.

    3.3.Effect of magnetic filter position

    In this section,the influence of the magnetic filter position on the negative hydrogen ion density is investigated at 40 kW and 0.6 Pa, with the magnetic filter located at 0 cm(z = 25 cm), 6 cm (z = 19 cm) and 12 cm (z = 13 cm) from the bottom of the expansion region, respectively.Figure 10 shows the distributions of the magnetic field strength along the z-direction (i.e.x = 30 cm, y = 25 cm) at different magnetic filter positions.It can be seen that by moving the magnet in the opposite direction of the z-axis, the magnetic field penetrating into the driver region becomes stronger.

    3.3.1.x-z plane.Figure 11 shows the spatial profiles of the negative hydrogen ion density in the x-z plane without and with the magnetic filter placed at different positions.Compared with the case without the magnetic filter, there is a significant increase in H?density when the magnetic filter is placed at the bottom of the expansion region (z = 25 cm),with the maximum appearing on the right-hand side of the symmetric axis.As the magnet moves closer to the driver region, the H?density decreases, with the maximum shifting upwards and horizontally from the right-hand side of the symmetric axis to the left.

    Figure 14.Distributions of negative hydrogen ion density in the x-y plane (z = 20 cm) without and with a magnetic filter placed at different positions.

    In order to understand the negative hydrogen ion density distributions in the x-z plane for different magnetic filter positions, the local (collisions) and non-local (transport)processes are examined.The first row of figure 12 shows the distribution of the production and destruction rates of negative hydrogen ions.In the absence of the magnet, both the production and destruction rates are symmetrical.After introducing the magnet at z=25 cm, the maximum production rate moves to the right, while the maximum of destruction rate shifts to the left, due to the asymmetry of the electron temperature.Since electrons tend to rotate around magnetic field lines, the source term in the vicinity of the magnet exhibits a significant increase due to the lower electron temperature caused by the frequent collisions there.Under this condition, the positive source term mainly takes place on the right-hand side of the chamber.As the magnet moves to z=19 cm,the production rate continues to decrease and the destruction rate gets closer to the left wall[16].This is due to the fact that the stronger magnetic field in the driver region leads to a local increase in electron temperature,which limits the production of negative hydrogen ions.Moreover,the electron temperature gradient between the driver and expansion regions increases, which enhances the asymmetry.When the magnet is placed at z=13 cm,both the production and destruction rates in the driver region continue to increase.This is because the magnetic field is too strong, which suppresses the transport of electrons to the expansion region[32].Therefore, the electron density in the driver region becomes higher, as well as the production and destruction rates.The positive source term at the expansion region becomes less intense as the magnet moves upward [16].

    In addition, the distribution of H2(w = 2) density is shown in the second row of figure 12.When the permanent magnet is introduced, the maximum H2(w = 2) density moves to the left wall of the driver region and the value near the bottom wall of the expansion region decreases.As the magnet moves towards the driver region,the peak H2(w=2)density becomes more intense with higher absolute values due to the higher electron temperature.

    The first row of figure 13 shows the negative hydrogen ion flux, which is mainly determined by the drift under the electric field,as mentioned above.When the magnetic filter is introduced,the potential distribution becomes asymmetric,as can be seen in the second row of figure 13,and the asymmetry becomes more obvious as the magnet moves upwards.Therefore, the negative hydrogen ions transport towards the left wall of the driver region.

    The distribution of negative hydrogen ion density is determined by the combined effect of collisions and transport.When the magnet is located at z = 25 cm, the source term exhibits a maximum in the expansion region.Due to the dominant influence of collisions, the maximum negative hydrogen ion density appears on the right-hand side of the symmetric axis.When the magnet moves to z=13 cm,the transport plays a more important role as the value of the source term decreases, so the peak negative hydrogen ion density moves to the left-hand side of the driver region.

    3.3.2.x-y plane.Figure 14 shows the spatial profiles of the negative hydrogen ion density in the x-y plane (z = 20 cm)without and with the magnetic filter at different positions.When the magnetic filter is applied at z=25 cm,the negative hydrogen ion density is slightly higher than that in the case without the magnet.As the magnet moves towards the driver region, the density decreases monotonically and the symmetry becomes worse, with the maximum shifting from the left-hand side of the symmetric axis to the right.

    Moreover, as can be seen in the first row of figure 15,when the magnet is placed at z = 25 cm, the source term in the x-y plane is greater than 0, i.e.the production rate is higher than the destruction rate.As the magnet shifts upwards, both the production and destruction rates reduce,with the maximum moving to the right.Since excited hydrogen molecules H2(w = 2) play an important role in the production of negative hydrogen ions, their density is presented in the second row of figure 15.It is clear that the maximum H2(w=2) density appears on the left and decreases monotonically with the upward movement of the magnet.However, due to the dominant influence of the electron temperature,the maximum generation rate appears at the right-hand side as the magnet moves upwards.

    Figure 15.The source term of negative hydrogen ions(first row)and H2(w=2)density(second row)in the x-y plane(z=20 cm)without and with a magnetic filter placed at different positions.The black and white contour lines in the first row represent the production anddestruction rates of negative hydrogen ions.

    Figure 16.The flux of negative hydrogen ions(first row)and plasma potential(second row)in the x-y plane(z=20 cm)without and with a magnetic filter placed at different positions.The arrows in the first row represent the direction of flux.

    From figure 16, it is clear that the negative hydrogen ion flux gradually decreases as the magnet moves upwards.Since collisions instead of transport play a dominant role at the bottom of the expansion region,the distribution of the negative hydrogen ion density is consistent with the source term.

    4.Conclusion

    In this paper, a 3D self-consistent fluid model with a levellumping strategy is employed to investigate an RF NHIS under various discharge conditions, with the volume production of H?ions taken into account self-consistently.First,the influence of the pressure on the negative hydrogen ion density is investigated.As pressure increases, the negative hydrogen ion density in the x-z plane increases, with the maximum moving from the left-hand side of the symmetric axis to the right.The evolution of the negative hydrogen ion density can be explained by the combined effect of local and non-local processes.Indeed, as pressure increases, collisions instead of transport play a dominant role.In the x-y plane,the negative hydrogen ion density first increases with pressure and then decreases, indicating that the transport from the driver region to the expansion region is suppressed at high pressure.In addition, when a magnetic filter is placed at the bottom of the expansion region, the negative hydrogen ion density in the x-z plane increases significantly and the asymmetry becomes obvious.As the magnet moves upward,the negative hydrogen ion density decreases, with the maximum shifting upwards to the left-hand side of the driver region.This can be explained by transport becoming dominant as the magnet moves upward.In the x-y plane,the source term is greater than 0 and the negative hydrogen ion density distribution is mainly determined by collisions.Both the density and symmetry of the negative ions at the bottom of the expansion chamber are reduced during the process of changing the magnet’s position toward the driver region.

    The results show that the volume production of negative hydrogen ions could be optimized (i.e.higher density and better symmetry) at 1 Pa when the magnetic filter is placed away from the driver region under the conditions used in this work.

    Acknowledgments

    This work was supported by the National Key R&D Program of China (No.2017YFE0300106), National Natural Science Foundation of China(Nos.11935005 and 12075049)and the Fundamental Research Funds for the Central Universities(Nos.DUT21TD104 and DUT21LAB110).

    猜你喜歡
    王友英杰
    Conductivity effects during the transition from collisionless to collisional regimes in cylindrical inductively coupled plasmas
    High energy electron beam generation during interaction of a laser accelerated proton beam with a gas-discharge plasma
    急性子的媽媽
    Multi-layer structure formation of relativistic electron beams in plasmas
    Influence of magnetic filter field on the radiofrequency negative hydrogen ion source of neutral beam injector for China Fusion Engineering Test Reactor
    Probability density and oscillating period of magnetopolaron in parabolic quantum dot in the presence of Rashba effect and temperature*
    Spatio-temporal measurements of overshoot phenomenon in pulsed inductively coupled discharge?
    Measurement of electronegativity during the E to H mode transition in a radio frequency inductively coupled Ar/O2 plasma?
    Observe modern design works and taste traditional Chinese culture
    Special Property of Group Velocity for Temporal Dark Soliton?
    亚洲在久久综合| 色94色欧美一区二区| 国产熟女欧美一区二区| 成人亚洲精品一区在线观看| 母亲3免费完整高清在线观看 | 亚洲成人av在线免费| 国产精品偷伦视频观看了| 亚洲国产av新网站| 在线观看国产h片| 2021少妇久久久久久久久久久| 午夜精品国产一区二区电影| 欧美日本中文国产一区发布| 国产黄频视频在线观看| 在线观看国产h片| 男人爽女人下面视频在线观看| 欧美成人精品欧美一级黄| 在线观看免费视频网站a站| 欧美日本中文国产一区发布| 中文欧美无线码| 一边亲一边摸免费视频| 国产亚洲精品久久久com| 午夜精品国产一区二区电影| 欧美激情极品国产一区二区三区 | 久久精品久久久久久久性| 涩涩av久久男人的天堂| 美女脱内裤让男人舔精品视频| 国产精品偷伦视频观看了| 国产国拍精品亚洲av在线观看| av电影中文网址| 日韩制服丝袜自拍偷拍| 人妻 亚洲 视频| 精品少妇黑人巨大在线播放| 日韩成人伦理影院| 午夜福利,免费看| 一级片免费观看大全| 国产精品国产三级国产av玫瑰| 日韩成人av中文字幕在线观看| 亚洲av免费高清在线观看| 内地一区二区视频在线| 亚洲经典国产精华液单| 观看av在线不卡| av天堂久久9| 九色亚洲精品在线播放| 亚洲精品久久成人aⅴ小说| 国产精品久久久久久久电影| 69精品国产乱码久久久| 最近中文字幕高清免费大全6| 国产精品国产三级国产专区5o| 美女中出高潮动态图| 插逼视频在线观看| 国产国拍精品亚洲av在线观看| 婷婷色综合www| 亚洲精品一区蜜桃| 黑丝袜美女国产一区| 99香蕉大伊视频| 中文字幕最新亚洲高清| 丰满饥渴人妻一区二区三| 精品人妻在线不人妻| 国产精品久久久久久久电影| 国产成人免费观看mmmm| 五月天丁香电影| 亚洲第一av免费看| 久久人妻熟女aⅴ| 精品久久久久久电影网| 91久久精品国产一区二区三区| 人人妻人人添人人爽欧美一区卜| 大码成人一级视频| 女人精品久久久久毛片| 久久人人爽人人爽人人片va| 日本午夜av视频| 欧美日韩成人在线一区二区| 日本色播在线视频| 少妇被粗大猛烈的视频| 婷婷色综合大香蕉| 亚洲精品自拍成人| 在线天堂中文资源库| 亚洲,欧美,日韩| a级片在线免费高清观看视频| 成人亚洲精品一区在线观看| 七月丁香在线播放| 欧美日韩av久久| 夜夜爽夜夜爽视频| 国产女主播在线喷水免费视频网站| xxx大片免费视频| 国产亚洲精品久久久com| 免费黄频网站在线观看国产| 中文字幕人妻丝袜制服| 精品久久蜜臀av无| 99久国产av精品国产电影| 飞空精品影院首页| videosex国产| 亚洲av.av天堂| 嫩草影院入口| 国产乱人偷精品视频| 大香蕉久久网| 日韩不卡一区二区三区视频在线| 日日爽夜夜爽网站| 亚洲精品一区蜜桃| 久久久久久久久久人人人人人人| 亚洲美女视频黄频| 一级毛片我不卡| 欧美丝袜亚洲另类| 女人久久www免费人成看片| 欧美日韩成人在线一区二区| 欧美国产精品一级二级三级| 水蜜桃什么品种好| 18禁国产床啪视频网站| 香蕉国产在线看| 搡老乐熟女国产| 狂野欧美激情性bbbbbb| 成人午夜精彩视频在线观看| 国产精品成人在线| 国产1区2区3区精品| 欧美日韩亚洲高清精品| 国产有黄有色有爽视频| 男女国产视频网站| 国产国拍精品亚洲av在线观看| 97人妻天天添夜夜摸| 日韩精品免费视频一区二区三区 | 搡老乐熟女国产| 国产无遮挡羞羞视频在线观看| 99re6热这里在线精品视频| 91aial.com中文字幕在线观看| 丰满迷人的少妇在线观看| 韩国av在线不卡| 热99久久久久精品小说推荐| 国产熟女午夜一区二区三区| 男男h啪啪无遮挡| 国产深夜福利视频在线观看| 精品国产露脸久久av麻豆| 成人国产av品久久久| 乱人伦中国视频| 国产精品国产三级国产av玫瑰| 全区人妻精品视频| 亚洲成人av在线免费| 五月开心婷婷网| 亚洲中文av在线| 全区人妻精品视频| 全区人妻精品视频| 久久99精品国语久久久| 免费播放大片免费观看视频在线观看| 美女国产视频在线观看| 国产男人的电影天堂91| 色哟哟·www| av在线播放精品| 大片免费播放器 马上看| 亚洲精品日本国产第一区| 免费黄网站久久成人精品| 亚洲人成77777在线视频| 中国三级夫妇交换| 丝袜脚勾引网站| 另类亚洲欧美激情| 亚洲熟女精品中文字幕| 丝袜美足系列| 午夜影院在线不卡| 黄片无遮挡物在线观看| 大片免费播放器 马上看| 在线观看人妻少妇| 亚洲一区二区三区欧美精品| 天美传媒精品一区二区| 男女午夜视频在线观看 | 卡戴珊不雅视频在线播放| 国产日韩欧美亚洲二区| 亚洲一区二区三区欧美精品| 国产av国产精品国产| 亚洲av在线观看美女高潮| 99国产综合亚洲精品| 色婷婷av一区二区三区视频| 97精品久久久久久久久久精品| 国产伦理片在线播放av一区| www.色视频.com| 大片免费播放器 马上看| 国产一区有黄有色的免费视频| 成人毛片60女人毛片免费| 国产精品三级大全| 女的被弄到高潮叫床怎么办| 欧美xxⅹ黑人| 午夜免费鲁丝| 十八禁高潮呻吟视频| 永久免费av网站大全| 2018国产大陆天天弄谢| 中文字幕亚洲精品专区| 最近最新中文字幕大全免费视频 | 看免费成人av毛片| 亚洲精品自拍成人| 美女主播在线视频| 9热在线视频观看99| 久久97久久精品| 校园人妻丝袜中文字幕| 亚洲精品日本国产第一区| 久久99热6这里只有精品| 极品少妇高潮喷水抽搐| 亚洲第一av免费看| 在线精品无人区一区二区三| 熟女电影av网| 制服诱惑二区| 国产亚洲午夜精品一区二区久久| 女人被躁到高潮嗷嗷叫费观| 成人毛片60女人毛片免费| 综合色丁香网| 日日啪夜夜爽| 久久99蜜桃精品久久| 丰满少妇做爰视频| 一本一本久久a久久精品综合妖精 国产伦在线观看视频一区 | 中文天堂在线官网| 丝袜美足系列| 一本一本久久a久久精品综合妖精 国产伦在线观看视频一区 | 久久久久视频综合| 亚洲国产欧美日韩在线播放| a级毛片在线看网站| 久久精品久久精品一区二区三区| 男人添女人高潮全过程视频| 99热国产这里只有精品6| 色婷婷久久久亚洲欧美| 女人久久www免费人成看片| 少妇的逼好多水| 欧美亚洲日本最大视频资源| 久久免费观看电影| 春色校园在线视频观看| 久久鲁丝午夜福利片| 一本色道久久久久久精品综合| 亚洲欧美日韩另类电影网站| 99视频精品全部免费 在线| 久久久精品94久久精品| 乱码一卡2卡4卡精品| 丝袜人妻中文字幕| av不卡在线播放| 亚洲国产精品999| 少妇人妻久久综合中文| 日韩一区二区三区影片| 亚洲一码二码三码区别大吗| 丝袜美足系列| 免费看光身美女| 有码 亚洲区| 成年av动漫网址| 亚洲av欧美aⅴ国产| av在线播放精品| 在线观看免费视频网站a站| 26uuu在线亚洲综合色| 免费日韩欧美在线观看| 女性生殖器流出的白浆| 黄片播放在线免费| 久热这里只有精品99| 一区二区三区精品91| 午夜福利影视在线免费观看| 欧美成人午夜免费资源| 少妇的逼水好多| 免费日韩欧美在线观看| 国产深夜福利视频在线观看| 精品国产一区二区三区四区第35| 国产免费现黄频在线看| 国产熟女午夜一区二区三区| 五月伊人婷婷丁香| 国产精品人妻久久久影院| 国精品久久久久久国模美| 亚洲欧美一区二区三区国产| 新久久久久国产一级毛片| 久久精品国产亚洲av涩爱| 国产精品 国内视频| 视频区图区小说| 免费大片18禁| 熟女人妻精品中文字幕| 国产亚洲av片在线观看秒播厂| 亚洲国产看品久久| 久久久久久久久久久免费av| 日本与韩国留学比较| 国产精品人妻久久久影院| 国产成人a∨麻豆精品| 久久精品夜色国产| 久久久久久人妻| 精品少妇黑人巨大在线播放| 肉色欧美久久久久久久蜜桃| 久久99一区二区三区| 国产亚洲欧美精品永久| 观看美女的网站| 国产片特级美女逼逼视频| 日本91视频免费播放| 国产成人精品在线电影| 91aial.com中文字幕在线观看| 黄色怎么调成土黄色| tube8黄色片| 一区在线观看完整版| 人妻少妇偷人精品九色| 日本免费在线观看一区| 热re99久久国产66热| 免费在线观看完整版高清| 黑人高潮一二区| 久久久久久久国产电影| 国产精品成人在线| 亚洲精品成人av观看孕妇| 成年美女黄网站色视频大全免费| 国产免费一区二区三区四区乱码| 久久精品国产亚洲av涩爱| 精品久久国产蜜桃| 天天影视国产精品| 国产一区二区在线观看av| 国产亚洲一区二区精品| 2022亚洲国产成人精品| 亚洲精品日本国产第一区| 老司机影院毛片| 看免费av毛片| 国产精品不卡视频一区二区| 777米奇影视久久| 黑人巨大精品欧美一区二区蜜桃 | 久久精品久久久久久噜噜老黄| 国产免费视频播放在线视频| 亚洲少妇的诱惑av| 夫妻性生交免费视频一级片| 国产极品粉嫩免费观看在线| 观看美女的网站| 国产精品一二三区在线看| 秋霞伦理黄片| 亚洲精品美女久久av网站| 日本与韩国留学比较| 日韩不卡一区二区三区视频在线| 国产免费视频播放在线视频| 狠狠精品人妻久久久久久综合| 看免费成人av毛片| 国产一区二区在线观看日韩| 亚洲 欧美一区二区三区| 999精品在线视频| 亚洲久久久国产精品| 日韩不卡一区二区三区视频在线| 久久国内精品自在自线图片| 久久毛片免费看一区二区三区| 最新的欧美精品一区二区| 亚洲一码二码三码区别大吗| 成人毛片a级毛片在线播放| 两性夫妻黄色片 | 男女边吃奶边做爰视频| 一边摸一边做爽爽视频免费| 亚洲国产看品久久| 2022亚洲国产成人精品| 在线观看美女被高潮喷水网站| 亚洲人与动物交配视频| 精品国产一区二区三区四区第35| 午夜免费观看性视频| 国产女主播在线喷水免费视频网站| 亚洲欧美成人综合另类久久久| av卡一久久| 男人舔女人的私密视频| 日本-黄色视频高清免费观看| 在线观看三级黄色| 亚洲国产精品成人久久小说| 国产日韩欧美亚洲二区| 成人免费观看视频高清| 美女主播在线视频| 啦啦啦视频在线资源免费观看| 欧美亚洲日本最大视频资源| 亚洲成人av在线免费| 99久久中文字幕三级久久日本| 少妇熟女欧美另类| 天天操日日干夜夜撸| 热re99久久国产66热| 不卡视频在线观看欧美| 亚洲av电影在线观看一区二区三区| 久久婷婷青草| 国产精品人妻久久久影院| 国产乱人偷精品视频| 日韩伦理黄色片| 久久精品夜色国产| 男女边摸边吃奶| 老司机影院成人| 精品国产露脸久久av麻豆| 免费观看性生交大片5| 国产成人午夜福利电影在线观看| 97在线视频观看| 少妇精品久久久久久久| 草草在线视频免费看| 18禁动态无遮挡网站| 欧美日韩成人在线一区二区| 黄色视频在线播放观看不卡| 精品福利永久在线观看| 人妻少妇偷人精品九色| 汤姆久久久久久久影院中文字幕| 韩国高清视频一区二区三区| 五月伊人婷婷丁香| 久久久久久久国产电影| 99热网站在线观看| 免费少妇av软件| 精品午夜福利在线看| 午夜福利视频精品| 成年人免费黄色播放视频| 日本爱情动作片www.在线观看| 亚洲成av片中文字幕在线观看 | av国产久精品久网站免费入址| 黑丝袜美女国产一区| 人妻人人澡人人爽人人| 男女下面插进去视频免费观看 | 婷婷色综合大香蕉| 亚洲伊人色综图| av免费在线看不卡| 亚洲第一av免费看| 男女国产视频网站| 99国产精品免费福利视频| 国产探花极品一区二区| 丝袜美足系列| 亚洲欧美一区二区三区黑人 | 成年女人在线观看亚洲视频| 免费久久久久久久精品成人欧美视频 | 国产爽快片一区二区三区| 免费播放大片免费观看视频在线观看| 国产在线一区二区三区精| 桃花免费在线播放| 男女无遮挡免费网站观看| 免费av中文字幕在线| 日韩在线高清观看一区二区三区| 最近中文字幕高清免费大全6| 伦理电影大哥的女人| 午夜91福利影院| 国产av码专区亚洲av| 国产精品久久久久成人av| 国产女主播在线喷水免费视频网站| 午夜老司机福利剧场| 免费大片黄手机在线观看| 亚洲精品日韩在线中文字幕| 波多野结衣一区麻豆| 日韩免费高清中文字幕av| 国产精品不卡视频一区二区| 欧美精品av麻豆av| 久久婷婷青草| 一级毛片 在线播放| 男人舔女人的私密视频| 中文欧美无线码| 侵犯人妻中文字幕一二三四区| 插逼视频在线观看| 男男h啪啪无遮挡| 亚洲精品美女久久av网站| 色哟哟·www| 欧美97在线视频| 日本wwww免费看| 久久久久久久大尺度免费视频| 免费高清在线观看视频在线观看| 99久久精品国产国产毛片| 成人免费观看视频高清| 成人漫画全彩无遮挡| 国产黄色视频一区二区在线观看| 黑丝袜美女国产一区| 97超碰精品成人国产| 中文字幕另类日韩欧美亚洲嫩草| 99国产精品免费福利视频| 满18在线观看网站| 成人国语在线视频| av女优亚洲男人天堂| 国产男女超爽视频在线观看| 国产黄频视频在线观看| 大片免费播放器 马上看| 久久久a久久爽久久v久久| 日本免费在线观看一区| 亚洲,一卡二卡三卡| 超碰97精品在线观看| 国产成人精品在线电影| 日韩中文字幕视频在线看片| 三上悠亚av全集在线观看| 满18在线观看网站| 国产成人免费观看mmmm| 久久久久久伊人网av| 国产综合精华液| 高清毛片免费看| 熟女电影av网| 最新中文字幕久久久久| 9191精品国产免费久久| 亚洲性久久影院| 日本vs欧美在线观看视频| 婷婷色av中文字幕| 日韩熟女老妇一区二区性免费视频| 国产成人av激情在线播放| 新久久久久国产一级毛片| 边亲边吃奶的免费视频| 国产亚洲精品久久久com| 高清视频免费观看一区二区| 欧美国产精品一级二级三级| 亚洲五月色婷婷综合| 在线天堂最新版资源| 国产精品久久久久久av不卡| 亚洲国产毛片av蜜桃av| 大香蕉久久成人网| 一级片'在线观看视频| 老司机影院成人| 精品少妇黑人巨大在线播放| 极品人妻少妇av视频| 亚洲精品中文字幕在线视频| 看十八女毛片水多多多| 男人操女人黄网站| 久久国内精品自在自线图片| 午夜精品国产一区二区电影| 街头女战士在线观看网站| 最近手机中文字幕大全| av在线app专区| 一级毛片黄色毛片免费观看视频| 国产日韩一区二区三区精品不卡| 9热在线视频观看99| 国产探花极品一区二区| 在线观看免费日韩欧美大片| 久久精品久久精品一区二区三区| 国产欧美日韩一区二区三区在线| 国产成人精品福利久久| 国产黄频视频在线观看| 国精品久久久久久国模美| 丁香六月天网| 久久99一区二区三区| 综合色丁香网| av视频免费观看在线观看| 日韩一本色道免费dvd| 亚洲欧洲国产日韩| 国产精品三级大全| a级毛片黄视频| 少妇的逼水好多| 日韩伦理黄色片| 国产一级毛片在线| 日本av免费视频播放| 亚洲精品国产av成人精品| 国产精品国产三级专区第一集| 在现免费观看毛片| 两性夫妻黄色片 | 日本欧美国产在线视频| 国产极品天堂在线| 熟女人妻精品中文字幕| 免费播放大片免费观看视频在线观看| 中文字幕亚洲精品专区| 午夜福利网站1000一区二区三区| 免费av不卡在线播放| 国产免费一区二区三区四区乱码| 亚洲精品视频女| 少妇人妻精品综合一区二区| 欧美bdsm另类| 香蕉精品网在线| 在线观看三级黄色| 午夜影院在线不卡| 视频中文字幕在线观看| 免费人成在线观看视频色| 久久精品久久精品一区二区三区| av在线app专区| 精品人妻熟女毛片av久久网站| 两个人看的免费小视频| 免费观看在线日韩| 久久午夜福利片| 婷婷色麻豆天堂久久| av线在线观看网站| 草草在线视频免费看| 久久毛片免费看一区二区三区| av卡一久久| 国产精品 国内视频| 欧美成人午夜精品| 如日韩欧美国产精品一区二区三区| 亚洲四区av| 国产成人精品久久久久久| 99久久精品国产国产毛片| 久久女婷五月综合色啪小说| 水蜜桃什么品种好| 少妇人妻久久综合中文| 香蕉精品网在线| 九色成人免费人妻av| 久久久久国产网址| 国产综合精华液| 亚洲av日韩在线播放| 中文字幕亚洲精品专区| 国产精品秋霞免费鲁丝片| 久久久欧美国产精品| 性色avwww在线观看| 色网站视频免费| 性色av一级| 国产男人的电影天堂91| 麻豆乱淫一区二区| 亚洲国产精品专区欧美| 久久av网站| 黑人欧美特级aaaaaa片| 亚洲国产精品一区二区三区在线| 午夜精品国产一区二区电影| 菩萨蛮人人尽说江南好唐韦庄| 18禁国产床啪视频网站| 国产亚洲精品久久久com| 肉色欧美久久久久久久蜜桃| 飞空精品影院首页| 欧美国产精品一级二级三级| 精品人妻在线不人妻| 成人无遮挡网站| 国产精品无大码| 午夜精品国产一区二区电影| 男女国产视频网站| 欧美日韩一区二区视频在线观看视频在线| 亚洲精品国产av成人精品| 亚洲天堂av无毛| 国产精品久久久久久精品古装| 日韩av免费高清视频| 久久女婷五月综合色啪小说| 春色校园在线视频观看| 最黄视频免费看| 亚洲人成网站在线观看播放| 激情五月婷婷亚洲| 大陆偷拍与自拍| 国产一级毛片在线| av福利片在线| 蜜桃在线观看..| 国产精品熟女久久久久浪| 国产免费一级a男人的天堂| 久久久久久久国产电影| 中国国产av一级| 91精品三级在线观看| 黄色视频在线播放观看不卡| 婷婷色麻豆天堂久久| 国产日韩欧美在线精品| 国产一区亚洲一区在线观看| 欧美日本中文国产一区发布| 我的女老师完整版在线观看| 久久久久国产网址| 亚洲,一卡二卡三卡| 汤姆久久久久久久影院中文字幕| 在线观看美女被高潮喷水网站| 国产在线免费精品| 久久国产亚洲av麻豆专区| 只有这里有精品99| 成年女人在线观看亚洲视频| 久久久国产一区二区| 久久精品aⅴ一区二区三区四区 |