• <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 ?

    Effects of trapped electrons on the ion temperature gradient mode in tokamak plasmas with hollow density profiles

    2020-06-14 08:45:22JingchunLI李景春JiaqiDONG董家齊andSongfenLIU劉松芬
    Plasma Science and Technology 2020年5期
    關(guān)鍵詞:董家

    Jingchun LI (李景春),Jiaqi DONG (董家齊) and Songfen LIU (劉松芬)

    1 School of Physics,Nankai University,Tianjin 300071,People’s Republic of China

    2 University of California,Irvine,CA 92697,United States of America

    3 School of Physics and Optoelectronic Technology,Dalian University of Technology,Dalian 116024,People’s Republic of China

    4 Southwestern Institute of Physics,Chengdu 610041,People’s Republic of China

    Abstract

    Keywords:micro-instabilities,trapped electrons,impurities

    1.Introduction

    In tokamaks,ion temperature gradient(ITG)driven instability is one of the drift waves and is considered a major factor for ion-scale turbulent transport.The ITG modes also have an important effect on the low(L)to high(H)confinement mode transition and energy confinement [1].The hollow (inverted)density profile occurs simultaneously with the pellet injection for plasma core fueling and L-H confinement transition[2–5].The study of drift wave instability under the hollow density profile and the turbulent transport caused by it can provide guidance for a pellet fueling experiment.Besides,it is well known that impurity ions are inevitably present in toroidal fusion plasma due to the inevitable interaction between the plasma and the first wall material.These impurity ions have significant effects on drift waves.Therefore,it is important to investigate the impurity ions effect on the ITG mode under a hollow density profile.

    On the one hand,the ITG mode as well as the effect of impurities on it has been intensively studied theoretically and experimentally in the case of a monotonically decreasing density profile(R/Ln> 0)[6–8].The study of the ITG driven mode with impurities in toroidal plasmas was first investigated in[9].Later on,the effect of impurities on the ITG was also carried out in the reversed field pinch [10,11].On the other hand,in terms of the inverted density distribution(R/Ln<0),previous work on the ITG mode has not been systematic[12,13].Early theoretical studies include the calculations from Tang and Hahm [13,14].Their results showed that in the case of a negative density gradient,the ITG mode becomes unstable as the temperature gradient of ions exceed a certain critical threshold.Adam et al [15]demonstrated that the inverted density profile can cause particles to transport radially inward,which means,to some extent,that the profile is advantageous for fusion confinement.

    Recently,studies relating to hollow density profiles have been carried out on many magnetic confinement fusion devices[16–21],such as the Mega Ampere Spherical Tokamak(MAST),Joint European Torus (JET),Axially Symmetric Divertor Experiment(ASDEX Upgrade),and the Large Helical Device (LHD).In addition,Tegnered et al [22]studied the transport of turbulent particles caused by ITG modes and trapped electron modes (TEM) under a hollow density distribution using the gyrokinetic code GENE and the Weiland Fluid Transport Model.It was found that the negative density gradient can suppress turbulence or change the relationship between diffusion and convection,and weaken the transport of particles to the core,thereby reducing the efficiency of fueling.Dong et al studied the electron temperature gradient (ETG)driven instabilities in plasmas with slightly inverted density profiles and demonstrated the E × B flow shear stabilization on the ETG modes,as well as on the transport[23].More recently,Du et al[24]used the local gyrokinetic eigenvalue code HD7[25,26]to simulate the ITG and TEM numerically under a hollow profile,and efficiently scanned the key parameters(i.e.,density gradient,temperature gradient,temperature ratios,and vertical wave numbers) affecting the ITG mode and TEM instability threshold and intensity.However,their research did not consider the effects of impurities.Impurities are inevitable in magnetic confinement fusion experiments,which not only cause a large amount of energy loss in the plasma,but also affect various instabilities in the plasma.They will in turn affect the distribution of the plasma parameters and confinement performance [27,28].

    In this paper,we incorporate the trapped electrons (TEs)and impurities in the calculations,and systematically investigate the effects of TEs and impurities on the ITG modes in inverted density tokamak plasmas by adopting the gyrokinetic integral eigenmode scheme in a toroidal configuration.Our kinetic simulations found that in inverted density plasma,the increase of the ITG enhances the ITG growth rate and frequency.For the weak density gradient situation,the impurities(O+6)can decrease the growth rate as well as frequency of the ITG mode distinctly,and the greater the fraction of impurities,the greater the influence of inhibition of impurities on the the ITG mode.For the strong density gradient cases,impurities enhance the ITG instability,and the TE has a suppression effect on the modes.In addition,it is shown that the growth rate of the ITG decreases with the increase of positive magnetic shear s,while the real frequency increases with the increase of positive magnetic shear s.Furthermore,the growth rate of the ITG enhances while the real frequency decreases with the decrease of negative magnetic shear s.The relationship between the ITG mode and magnetic shear is emphasized for both slight and strong hollow density profiles in tokamak plasmas.

    The remainder of this paper is organized as follows.The gyrokinetic equation and physical model are introduced in section 2.The numerical results of the ITG modes in an inverted density plasma edge with impurities are presented and analyzed in section 3.Finally,a brief conclusion is presented in section 4.

    2.Physical model

    To begin with,to make the structure of the article more complete,we first present the local gyrokinetic integral scheme used in this paper.We use the ballooning mode representation to study the ion-scale drift wave instability in tokamak plasma,with the linear mode coupling caused by the configuration of the toroidal magnetic field taken into account.The main ions in the system are hydrogen ions,and different ionized states of lithium,carbon,oxygen,nickel,tungsten,etc.are impurity ions.The main ions and impurity ions are all passing particles,which are described by a gyrokinetic model.In a toroidal geometry system with circular cross-sections,we consider the full kinetic effects of the main and impurity ions,such as magnetic field curvature and gradient drifts,finite Larmor radius (FLR) effects,and wave-particle resonance effects.Here,we ignore the FLR effect of the TEs and believe that the passing electrons are subject to adiabatic response.

    When considering the effects of TEs and impurity ions,low-frequency electrostatic disturbances in non-uniform plasmas can be described by quasi-neutral conditions:

    In the ballooning representation and with the gyrokinetic equation,the non-adiabatic response of the particle is governed by:

    where the magnetic(gradient and curvature)drift frequency is

    The diamagnetic drift frequency induced by the pressure gradient is:

    The definitions of the other parameters are as follows.The transit frequency isωt=v‖Rq,and the electron diamagnetic drift frequency isω*e=ck θTeeBLne,vtj=The non-adiabatic response of the TEs can be achieved by expanding equation(3)withω/ωbe,whereωbeis the bouncing frequency of the TEs.When ignoring the FLR of the TEs,the density perturbation of the TEs can be expressed as

    The precession drift frequency of the TEs is written as

    After complex mathematical operations,we obtain the expression of the integral eigenequation corresponding to equation (1):

    where

    The equation contains two types of ions,one is hydrogen ion,which are the main ion in the plasma,and the other is called impurity ion because of their small fraction.Among them

    Herek,k',kθis normalized to=Ωi/vti=andIl(l=0,1)is the modifeid l-order Bessel function.All symbols have their general meaning,such as the density gradient scale lengthLnj=-nj/?nj,undisturbed plasma density n0,temperature gradient scale lengthLTj=-Tj/?Tj,safety factor q,and magnetic shears=rdq/qdr.Z is the ion charge number,mjandTjare ion mass and temperature,and R is the major radius of the torus.It should be noted that not all parameters are independent,for example,based on quasi-neutral conditions,

    While assumingTi(r)=Tz(r),we achieve

    The parametersηi,ηe,εnand other parameters in the equation will influence the dispersion relationship.We use the gyrokinetic integral code HD7 to discuss their effects in the next section.

    3.Numerical results and analysis

    We now study the effect of impurity on the ITG mode with different temperatures and density gradients with the gyrokinetic integral eigenvalue code HD7.Compared with the nonlinear simulation,the limitation of linear simulation here is that the turbulence saturation amplitude cannot be obtained,and the relationship between microscopic instability and turbulence cannot be studied.However,linear simulation is still necessary:(i)it can determine the possible driving mechanism and instability conditions;(ii) when the transport caused by turbulence dominates,the plasma density and temperature gradient may be adjusted to be close to the threshold predicted by the linear instability theory;(iii) the temporal and spatial characteristics of the linear mode may be related to the turbulent flow,which can provide a rough estimate of the turbulent transport.We investigate the influence of other parameters like impurity species and magnetic shear on the ITG instabilities.In our calculations,since we consider hollow density profile plasma,Lez=Lne/Lnz> 0 means that the density gradients of the impurity and main ions are in the same direction,namely,impurities are peaked toward the plasma edge.Lez< 0 means that the density gradients are in opposite directions.

    Figure 1.Normalized growth rate (γ) and real frequency (ωr) of the ITG versus R/LTi for different impurity charge concentrations fz.The other parameters are s=0.8,q=1.4,kθρs=0.4,Lez=2,ηe=1,and R/Lne=–1.O+6 is treated as impurities.

    Figure 2.Normalized growth rate (γ) and real frequency (ωr) of the ITG versus R/LTi for different impurity charge concentrations fz.The other parameters are s=0.8,q=1.4,kθρs=0.6,Lez=2,ηe=1,and R/Lne=–8.O+6 is treated as impurities.

    3.1.Dependence on the ITG

    The normalized growth rate(γ)and the real frequency(ωr)of pure ITG modes versus R/LTiare presented in figures 1(a)and (b),respectively,where the length of the normalized electron temperature gradient scale R/LTeis equal to the length of the electron density gradient scale R/Lne.It must be explained here that the black dotted line represents the result of no impurities,i.e.,fz=0.We can see that the increase of the ITG enhances both the growth rate and frequency of the ITG modes,and impurities decrease the growth rate as well as frequency of the ITG mode distinctly.The higher the fraction of impurity O+6,the greater the suppression effect of the ITG.This suggests that the ITG modes are damped by impurity ions.The stabilizing effect of impurities is consistent with previous research results,because when the gradient of the impurity ions is the same as the electron density gradient,the dominant ion density is diluted (the relationship between the ion density gradient and the fraction of impurities is presented by equation(8))[28–32],which makes the impurity ion effect weaken the driving force of the ITG and stabilizes the ITG mode.

    Figure 2 is the same as figure 1 except that it has a strong density gradientLne=-ne/?ne=–8.Compared with figure 1,the real frequency of the ITG in figure 2 is lower.Most importantly,the impurity increases the growth rate of the ITG mode,which is very different in the weak density gradient case.For the strong density gradient,we have to consider the gradient of the main ion density.We have Lez=Lne/Lnzand Lei=Lne/Lni.Since Lezis positive while Lneis negative,this leads to the gradient of the impurity ion density being the same as that of the main ion density,which increases the ion density gradient and enhances the driving force.Therefore,the effect of impurities is destabilizing.

    Figure 3.Normalized growth rate (γ) and real frequency (ωr)versus R/LTi for different cases.The other parameters are s=0.8,q=1.4,kθρs=0.6,and R/Lne=–1.O+6 (with fz=0.25) is treated as impurities when they are incorporated.

    Figure 4.Normalized growth rate (γ) and real frequency (ωr)versus R/LTi for different cases.The other parameters are s=0.8,q=1.4,kθρs=0.6,and R/Lne=–8.O+6 (with fz=0.25) is treated as impurities when they are incorporated.

    3.2.Effect of TEs

    Figure 3 shows the normalized growth rate (γ) and real frequency(ωr)versus R/LTifor different cases,namely,with and without impurities,TEs.We set other parameters as:s=0.8,q=1.4,kθρs=0.6,and R/Lne=–1.As can be seen from figure 3,the impurity has a stabilizing effect on the ITG,and the TE can enhance the ITG instability,where the stabilization effect of the impurities is consistent with the previous simulation results.Concerning the destabilizing effect of TE,usually,when there are TEs,free energy is transferred from the TEs to the waves due to the precession drift resonance,so the TEs are destabilizing for the ITG.This resonance with TEs is related to the bounce average precession frequency(see equation (5)).The direction of the precession is in the toroidal direction.In fact,the resonance of TEs with the ITG mode is clearly represented by the denominator in the front of the integration overκd2in equation (5),which indicates that the resonance occurs between the mode oscillation(ω)and the bounce averaged precessional motionof TEs in the toroidal direction.Such resonance may have a destabilizing effect on the mode.

    The normalized growth rate (γ) and real frequency (ωr)versus R/LTifor different cases,namely,with and without impurities,TEs are presented in figure 4 with R/Lne=–8.The other parameters are the same as those shown in figure 3.We can see that there is a big difference between the TE effects between the weak and strong density gradient cases.In the weak density gradient situation,the TE effects tend to enhance the ITG instability,while the impurity has a clear stabilizing effect.However,in the strong density gradient cases,both the effects of impurities and TEs increase the ITG instability,especially the role of impurities,which makes the growth rate of instability increase by a large amplitude.This result in the hollow density profile plasma is exactly the opposite of that in plasmas with normal density gradient.We need to note that,generally speaking,for the former case,the total effect of TEs and impurity ions is stabilizing,while for the latter cases,the total effect is destabilizing.

    3.3.Effect of magnetic shear

    Numerous studies have shown that magnetic shear is an important parameter affecting instability,turbulent transport bifurcation,ion temperature profile invariance,and turbulent spreading.This is mainly because magnetic shear can affect the radial structure of the drift mode.In some experimental devices,the core weak magnetic shear discharge mode,which is listed as one of the candidates for the advanced operating modes of ITER,is studied.In this mode,the safety factor profile of the core is relatively flat and the magnetic shear is relatively small.A large number of studies have shown that the weak magnetic shear discharge pattern can well suppress the current-driven and fast MHD instability,but it is found that some slow-growing modes still grow,including microscopic drift instability.

    Figure 5.Normalized growth rate(γ)and real frequency(ωr)versus positive s with different Lez.(a)and(b)represent R/Lne=-1;(c)and(d) represents R/Lne=-8.Other parameters are set as:s=0.8,q=1.4,kθρs=0.4,and ηe=1.C+6 (fz=0.2) is treated as impurities.

    In this subsection,we investigate the effect of magnetic shear on ITG instability in inverted density plasma.For comparison,we chose R/Lne=–1 and R/Lne=–8,respectively,to compare the flat and steep electron density distributions to analyze the influences of magnetic shear on ITG instability.Figure 5 depicts the normalized growth rate (γ)and real frequency (ωr) versus positive magnetic shear s with different Lez.Figures 5(a) and (b) represent R/Lne=–1;figures 5(c) and (d) represent R/Lne=–8.We set the other parameters as:s=0.8,q=1.4,kθρs=0.4,and ηe=1.C+6is treated as impurities.From figure 5,it is shown that the growth rate of the ITG mode decreases with positive magnetic shear s while the real frequency increases with positive magnetic shear.That means,large magnetic shear will suppress the growth of the ITG mode.A strong electron density gradient only changes the real frequency of the ITG mode,while it hardly affects the relationship between the ITG mode and the magnetic shear.

    Figure 6 is the same as figure 5,except the magnetic shear is negative.From figure 6,we can see that the growth rate of the ITG increases with negative magnetic shear s while the real frequency decreases with the decrease of negative magnetic shear.This indicates that the ITG mode will also be suppressed with larger negative magnetic shear s.It should be noted that under the steep electron density distribution,the effects of impurities on the ITG shown in figures 2 and 5 are different.This is because we do not consider TEs in figure 2,and in figure 5 we do consider TEs.If figure 5 does not incorporate TEs,figures 2 and 5 are consistent under a negative strong density gradient.

    3.4.Eigenmode structure

    In this subsection,we discuss the eigenmode structure of the ITG modes in the ballooning space.To compare the results,we use s=0.9 and s=–0.9 to discuss the characteristics of the ITG in the negative and positive magnetic shear intervals,respectively.The red solid line and the blue dashed line represent the real partand the imaginary partof the disturbing electrostatic potential,respectively,in figure 7,which shows the eigenmode structures of the ITG in θ-space with s=0.9.Figures 7(a)–(c) represent R/Lne=–1 and figures 7(d)–(f) represent R/Lne=–8.Other parameters are set the same as those in figure 5.Figure 8 is the same except s=–0.9.For positive s,we can see that the eigenmode structure is well localized in the ballooning space.For negative s,the eigenmode is elongated along the direction of the magnetic field lines,thus requiring a higher calculation accuracy.As shown in figures 7 and 8,the length calculated in the negative s interval is greater than the value in the positive s.In addition,we learn that for relatively large electron density gradients,the ITG mode structure has oscillations in the θ-space.

    4.Summary and discussion

    In this paper,with a local equilibrium model,the local properties of the ITG mode in tokamak plasmas of inverted density profiles are studied in the presence of impurity ions and TEs,using the gyrokinetic integral eigenvalue code HD7.The specific results obtained can be summarized as follows.

    Figure 6.Normalized growth rate(γ)and real frequency (ωr)versus negative s with different Lez.(a)and(b)represent R/Lne=–1;(c)and(d) represent R/Lne=–8.Other parameters are set as:s=0.8,q=1.4,kθρs=0.4,and ηe=1.Fully ionized carbon (C+6,fz=0.2) is treated as impurity species.

    Figure 7.Eigenmode structures of the ITG in the(θ)space with s=0.9.(a)–(c)represent R/Lne=–1;(d)–(f)represent R/Lne=–8.Other parameters are set the same as those shown in figure 5.C+6 is treated as impurities with fz=0.2.

    Figure 8.Eigenmode structures of the ITG in the(θ)space with s=–0.9.(a)–(c)represent R/Lne=–1;(d)–(f)represent R/Lne=–8.Other parameters are set the same as those shown in figure 6.C+6 is treated as impurities with fz=0.2.

    (1) The increase of the ITG enhances the ITG growth rate and frequency.The effects of the TEs and impurity ions depend on the electron density gradient.In the weak density gradient situation,the TE effects tend to increase the ITG instability,while the impurity has a distinct stabilizing effect.However,in the strong density gradient cases,both the impurity and TEs increase the ITG instabilities.

    (2) The magnetic shear s is an important parameter affecting ITG instability.It is found that the growth rate of the ITG decreases with positive magnetic shear s while the real frequency increases with s.We also demonstrate that the growth rate of the ITG increases with negative s while the real frequency decreases with s.In addition,in inverted density plasma,the length of the calculated mode structure in the negative s interval is greater than that in the positive s case.

    Future work will include a quasi-linear study of TE and impurities effects on the ITG mode in toroidal plasmas with hollow density profiles.Moreover,electromagnetic simulations of the ITG in toroidal plasmas are also ongoing.

    Acknowledgments

    The authors would like to thank Huarong Du and Jia Li for fruitful discussions.This work is supported by the National Key R&D Program of China (Nos.2018YFE0303102 and 2017YFE0301702),US SciDAC GSEP,the NSFC (Nos.11905109 and 11947238),the China Postdoctoral Science Foundation (No.2018M640230),and the Fundamental Research Funds for the Central Universities,Nankai University (63191351).

    猜你喜歡
    董家
    董家鴻院士
    Exact surface energy and elementary excitations of the XXX spin-1/2 chain with arbitrary non-diagonal boundary fields
    A nonlinear wave coupling algorithm and its programing and application in plasma turbulences
    Neoclassical tearing mode stabilization by electron cyclotron current drive for HL-2M tokamak*
    大功率激電測深方法在豫西董家埝銀礦床勘查中的應(yīng)用
    學(xué)習(xí)是進步階梯,做不放棄的自己
    董家口
    紅巖(2018年6期)2018-11-16 12:27:24
    填成語
    老友(2018年3期)2018-01-22 04:01:48
    補唐詩慶建軍節(jié)
    老友(2017年8期)2017-02-07 03:19:24
    安丘董家莊漢畫像石墓主人之謎
    大眾考古(2014年2期)2014-06-26 08:29:32
    99热国产这里只有精品6| 免费观看在线日韩| 精品人妻偷拍中文字幕| 精品久久久精品久久久| 3wmmmm亚洲av在线观看| 亚洲第一区二区三区不卡| 亚洲在久久综合| av线在线观看网站| 中文字幕av电影在线播放| 精品熟女少妇av免费看| 亚洲成人一二三区av| 国模一区二区三区四区视频| 国产成人免费无遮挡视频| av天堂久久9| 在线播放无遮挡| 免费大片18禁| 成人手机av| 最新的欧美精品一区二区| 精品人妻偷拍中文字幕| 99精国产麻豆久久婷婷| 免费观看性生交大片5| 一级,二级,三级黄色视频| 极品少妇高潮喷水抽搐| 人人妻人人添人人爽欧美一区卜| 少妇 在线观看| 午夜福利视频在线观看免费| 夜夜爽夜夜爽视频| 久久久久精品性色| 亚洲国产精品一区二区三区在线| 国产 精品1| 欧美日韩视频高清一区二区三区二| 色婷婷av一区二区三区视频| 国产男人的电影天堂91| 我的女老师完整版在线观看| 国产av一区二区精品久久| 男人爽女人下面视频在线观看| 99九九线精品视频在线观看视频| 国产成人免费观看mmmm| 亚洲精品视频女| 亚洲国产精品专区欧美| 黑人猛操日本美女一级片| 精品久久久久久电影网| 精品国产露脸久久av麻豆| 99久国产av精品国产电影| 久久久久视频综合| 久久99一区二区三区| 国产欧美亚洲国产| 波野结衣二区三区在线| 久久亚洲国产成人精品v| 免费观看的影片在线观看| 一区二区三区精品91| 国产毛片在线视频| 中文字幕亚洲精品专区| 国产av一区二区精品久久| 麻豆成人av视频| 欧美+日韩+精品| 亚洲欧美中文字幕日韩二区| 欧美日韩视频精品一区| 久久久亚洲精品成人影院| 免费少妇av软件| 人妻 亚洲 视频| 男女免费视频国产| 日韩中字成人| 日本vs欧美在线观看视频| 这个男人来自地球电影免费观看 | 亚洲国产欧美在线一区| 蜜桃在线观看..| 热99久久久久精品小说推荐| 国产色爽女视频免费观看| 精品一品国产午夜福利视频| 亚洲成人一二三区av| 欧美精品高潮呻吟av久久| 久久精品熟女亚洲av麻豆精品| 一区二区日韩欧美中文字幕 | 亚洲怡红院男人天堂| 国产精品一区二区在线不卡| av国产久精品久网站免费入址| 乱人伦中国视频| 人人妻人人澡人人爽人人夜夜| 日韩精品有码人妻一区| 亚洲av免费高清在线观看| 一级爰片在线观看| 亚洲精品自拍成人| 观看美女的网站| 国产精品一二三区在线看| 制服丝袜香蕉在线| 婷婷色综合大香蕉| 国语对白做爰xxxⅹ性视频网站| av黄色大香蕉| 日韩一本色道免费dvd| 夫妻午夜视频| 欧美亚洲日本最大视频资源| 久久久久久久久久久免费av| 久久久国产一区二区| a 毛片基地| 80岁老熟妇乱子伦牲交| 91aial.com中文字幕在线观看| 综合色丁香网| 精品人妻一区二区三区麻豆| 天堂中文最新版在线下载| 精品午夜福利在线看| 老司机亚洲免费影院| 国产日韩欧美在线精品| 免费人妻精品一区二区三区视频| 久久韩国三级中文字幕| 免费黄网站久久成人精品| 国产免费现黄频在线看| 亚洲怡红院男人天堂| 一本大道久久a久久精品| 精品视频人人做人人爽| 汤姆久久久久久久影院中文字幕| 国产日韩一区二区三区精品不卡 | av.在线天堂| 国产男女内射视频| 热re99久久精品国产66热6| 久久精品国产亚洲av涩爱| 欧美日韩精品成人综合77777| 免费大片18禁| 黄色视频在线播放观看不卡| 国产在线免费精品| 高清毛片免费看| 国产精品一区www在线观看| 好男人视频免费观看在线| 国产精品久久久久成人av| 亚洲精品成人av观看孕妇| av视频免费观看在线观看| 视频在线观看一区二区三区| 亚洲欧美日韩卡通动漫| 日本欧美视频一区| 久久免费观看电影| 成人影院久久| 久久精品国产亚洲av天美| 九九在线视频观看精品| 亚洲精品国产色婷婷电影| 另类精品久久| 亚洲av二区三区四区| 十分钟在线观看高清视频www| 美女cb高潮喷水在线观看| 国产色婷婷99| 在线观看免费日韩欧美大片 | 蜜桃在线观看..| 26uuu在线亚洲综合色| 久久久精品94久久精品| 黑丝袜美女国产一区| 久久综合国产亚洲精品| 欧美bdsm另类| 国产精品成人在线| 国产午夜精品久久久久久一区二区三区| 91久久精品电影网| 美女大奶头黄色视频| av在线观看视频网站免费| 九九久久精品国产亚洲av麻豆| 大片电影免费在线观看免费| 国产男女内射视频| 日本猛色少妇xxxxx猛交久久| 9色porny在线观看| 在线观看免费高清a一片| 日本欧美国产在线视频| 午夜福利视频精品| 亚洲美女视频黄频| 如日韩欧美国产精品一区二区三区 | 亚洲美女视频黄频| 免费观看a级毛片全部| 一级a做视频免费观看| 国产亚洲精品久久久com| 亚洲国产欧美日韩在线播放| 少妇 在线观看| 99热全是精品| 国产视频首页在线观看| 男女国产视频网站| 高清不卡的av网站| av不卡在线播放| 亚洲少妇的诱惑av| av在线观看视频网站免费| 亚洲色图综合在线观看| 国产精品久久久久久精品古装| 欧美一级a爱片免费观看看| 97在线人人人人妻| 校园人妻丝袜中文字幕| 少妇人妻 视频| 亚洲精品色激情综合| 亚洲综合色惰| 日韩成人av中文字幕在线观看| 久久午夜福利片| 简卡轻食公司| 热re99久久精品国产66热6| 少妇精品久久久久久久| 成人手机av| av卡一久久| 18禁观看日本| 国产不卡av网站在线观看| 久久久精品免费免费高清| 香蕉精品网在线| 搡老乐熟女国产| 精品久久国产蜜桃| 少妇人妻久久综合中文| 成人国语在线视频| 国模一区二区三区四区视频| 亚洲国产色片| 欧美日韩亚洲高清精品| 你懂的网址亚洲精品在线观看| 精品午夜福利在线看| 嘟嘟电影网在线观看| 国产成人精品在线电影| 如日韩欧美国产精品一区二区三区 | 最近2019中文字幕mv第一页| 国产一区亚洲一区在线观看| 欧美亚洲 丝袜 人妻 在线| 国产精品一国产av| 久久久久久久久大av| 成人国产麻豆网| 国产高清国产精品国产三级| 美女视频免费永久观看网站| 亚洲av日韩在线播放| 日韩强制内射视频| 国产精品国产三级国产专区5o| 超碰97精品在线观看| 韩国高清视频一区二区三区| 国产一级毛片在线| 亚洲精品中文字幕在线视频| 精品人妻一区二区三区麻豆| tube8黄色片| 人妻 亚洲 视频| 久久久亚洲精品成人影院| 日本猛色少妇xxxxx猛交久久| 中文字幕亚洲精品专区| 精品熟女少妇av免费看| 亚洲综合色网址| 大香蕉97超碰在线| 亚洲综合精品二区| 国产亚洲最大av| 又大又黄又爽视频免费| 亚洲怡红院男人天堂| 中文精品一卡2卡3卡4更新| 亚洲精品国产色婷婷电影| 午夜免费鲁丝| 美女国产高潮福利片在线看| 亚洲情色 制服丝袜| 欧美日韩精品成人综合77777| 欧美另类一区| 春色校园在线视频观看| 亚洲不卡免费看| 国产成人精品福利久久| 亚洲天堂av无毛| 亚洲色图综合在线观看| 91精品伊人久久大香线蕉| 国产精品 国内视频| 亚洲精品亚洲一区二区| 亚洲熟女精品中文字幕| 一区二区av电影网| 一区在线观看完整版| 久久久久久久久大av| av在线播放精品| a级毛色黄片| 在线亚洲精品国产二区图片欧美 | 久久99一区二区三区| 97超视频在线观看视频| 熟妇人妻不卡中文字幕| 国产av精品麻豆| 亚洲色图 男人天堂 中文字幕 | 国产精品欧美亚洲77777| 26uuu在线亚洲综合色| 成人手机av| 亚州av有码| videossex国产| 久久久久久久久久久丰满| 欧美激情 高清一区二区三区| 99久久精品一区二区三区| 美女视频免费永久观看网站| 2021少妇久久久久久久久久久| 少妇人妻精品综合一区二区| 80岁老熟妇乱子伦牲交| 中文天堂在线官网| 国产片内射在线| 中文字幕精品免费在线观看视频 | 亚洲av二区三区四区| 欧美三级亚洲精品| 免费观看a级毛片全部| 男女国产视频网站| 亚洲国产毛片av蜜桃av| 亚洲av.av天堂| 国产69精品久久久久777片| 一个人看视频在线观看www免费| 夫妻性生交免费视频一级片| 免费av不卡在线播放| 免费高清在线观看日韩| 欧美最新免费一区二区三区| 亚洲激情五月婷婷啪啪| 视频区图区小说| 日本av手机在线免费观看| 内地一区二区视频在线| 欧美三级亚洲精品| 精品久久蜜臀av无| 日韩免费高清中文字幕av| 亚洲欧美日韩另类电影网站| 午夜精品国产一区二区电影| 精品人妻在线不人妻| av.在线天堂| 日韩中字成人| 少妇被粗大猛烈的视频| 亚洲欧洲精品一区二区精品久久久 | av国产久精品久网站免费入址| 久久精品国产亚洲网站| 中文字幕制服av| 国产免费现黄频在线看| 日本色播在线视频| 亚洲美女视频黄频| 国产成人精品婷婷| 九色成人免费人妻av| 日韩欧美精品免费久久| 人妻系列 视频| 亚洲精品久久成人aⅴ小说 | 久久99热6这里只有精品| 欧美xxⅹ黑人| 国产精品免费大片| 一区二区三区免费毛片| 中文字幕精品免费在线观看视频 | 在线观看免费高清a一片| 国产老妇伦熟女老妇高清| 如何舔出高潮| 午夜福利,免费看| 中国三级夫妇交换| 在线 av 中文字幕| 欧美老熟妇乱子伦牲交| freevideosex欧美| www.色视频.com| 色吧在线观看| 国产黄片视频在线免费观看| 在线观看www视频免费| 免费少妇av软件| 亚洲中文av在线| 日日撸夜夜添| 久久久国产欧美日韩av| 女人精品久久久久毛片| 国产乱人偷精品视频| 成人国产麻豆网| 亚洲精品成人av观看孕妇| 欧美老熟妇乱子伦牲交| 亚洲精品乱码久久久久久按摩| 午夜福利在线观看免费完整高清在| 全区人妻精品视频| 母亲3免费完整高清在线观看 | 在线观看美女被高潮喷水网站| 成人午夜精彩视频在线观看| 777米奇影视久久| 亚洲精品一区蜜桃| 我的老师免费观看完整版| 搡女人真爽免费视频火全软件| 国产片内射在线| 天堂8中文在线网| 午夜福利视频精品| 久久精品久久久久久久性| 精品少妇黑人巨大在线播放| 蜜臀久久99精品久久宅男| 啦啦啦在线观看免费高清www| 99热这里只有是精品在线观看| 这个男人来自地球电影免费观看 | 精品久久久久久久久av| 国产一区二区在线观看av| 伦理电影免费视频| 在现免费观看毛片| 亚洲国产毛片av蜜桃av| 高清视频免费观看一区二区| 国产精品一国产av| 少妇人妻精品综合一区二区| 亚洲精品,欧美精品| a级毛色黄片| 只有这里有精品99| 美女视频免费永久观看网站| 日韩精品有码人妻一区| 大片免费播放器 马上看| videos熟女内射| 免费大片黄手机在线观看| 看十八女毛片水多多多| 免费高清在线观看日韩| 亚洲精品日韩av片在线观看| 久久久久久久精品精品| 亚洲av免费高清在线观看| 亚洲国产精品国产精品| 国产永久视频网站| 国产片特级美女逼逼视频| 一个人看视频在线观看www免费| 国产欧美日韩综合在线一区二区| 国产成人免费观看mmmm| 日韩中文字幕视频在线看片| 国产日韩一区二区三区精品不卡 | 爱豆传媒免费全集在线观看| 在线观看美女被高潮喷水网站| 午夜免费观看性视频| 一边亲一边摸免费视频| 免费看不卡的av| 精品久久久久久久久av| 国产成人aa在线观看| 国产不卡av网站在线观看| 蜜臀久久99精品久久宅男| 日韩制服骚丝袜av| 免费不卡的大黄色大毛片视频在线观看| 免费观看性生交大片5| 在线观看www视频免费| 大香蕉久久网| 亚洲精品,欧美精品| xxxhd国产人妻xxx| 久久精品国产亚洲av涩爱| 一区二区三区四区激情视频| 乱人伦中国视频| 欧美最新免费一区二区三区| 亚洲欧洲国产日韩| 高清av免费在线| 好男人视频免费观看在线| 亚洲成人一二三区av| 伦精品一区二区三区| 这个男人来自地球电影免费观看 | av卡一久久| 三上悠亚av全集在线观看| 看免费成人av毛片| 日韩av在线免费看完整版不卡| 国产黄色免费在线视频| 日韩精品有码人妻一区| videossex国产| 精品一品国产午夜福利视频| 亚洲精品aⅴ在线观看| 高清av免费在线| 建设人人有责人人尽责人人享有的| 丰满迷人的少妇在线观看| 中文乱码字字幕精品一区二区三区| 在线观看人妻少妇| 永久网站在线| 少妇被粗大猛烈的视频| 久久影院123| 国产乱人偷精品视频| 交换朋友夫妻互换小说| 黑人欧美特级aaaaaa片| 日本欧美视频一区| 爱豆传媒免费全集在线观看| 精品99又大又爽又粗少妇毛片| 亚洲欧美精品自产自拍| 多毛熟女@视频| 国产综合精华液| 在线免费观看不下载黄p国产| 日本91视频免费播放| 久久久亚洲精品成人影院| 好男人视频免费观看在线| 97超碰精品成人国产| 制服诱惑二区| 精品国产国语对白av| 18+在线观看网站| 久久久久精品久久久久真实原创| 简卡轻食公司| 久久女婷五月综合色啪小说| 少妇丰满av| 久久ye,这里只有精品| 韩国高清视频一区二区三区| 99精国产麻豆久久婷婷| 精品久久国产蜜桃| 国产精品久久久久久精品古装| 全区人妻精品视频| 校园人妻丝袜中文字幕| 国产精品国产av在线观看| 成人国产麻豆网| 99久久精品国产国产毛片| 日韩电影二区| 亚洲av欧美aⅴ国产| av天堂久久9| 黄色欧美视频在线观看| 亚洲精品乱码久久久久久按摩| 久久青草综合色| 国产av一区二区精品久久| av天堂久久9| 精品酒店卫生间| 2021少妇久久久久久久久久久| 亚洲精品视频女| 欧美日韩亚洲高清精品| 日韩中文字幕视频在线看片| 国产精品不卡视频一区二区| 美女内射精品一级片tv| 国产永久视频网站| 中文字幕亚洲精品专区| 亚洲天堂av无毛| 国产精品久久久久久久久免| 亚洲精品乱码久久久久久按摩| 毛片一级片免费看久久久久| 久久影院123| 色婷婷久久久亚洲欧美| 免费高清在线观看视频在线观看| 国产爽快片一区二区三区| 日韩大片免费观看网站| 97在线人人人人妻| 菩萨蛮人人尽说江南好唐韦庄| 日本黄色片子视频| 国产免费一级a男人的天堂| 国模一区二区三区四区视频| 久久av网站| 黑人猛操日本美女一级片| tube8黄色片| 亚洲国产精品专区欧美| 久久人人爽人人片av| 三级国产精品欧美在线观看| 王馨瑶露胸无遮挡在线观看| 99久久精品一区二区三区| 国产精品国产三级国产av玫瑰| 国产淫语在线视频| 啦啦啦中文免费视频观看日本| av.在线天堂| 国产精品国产三级国产专区5o| 超色免费av| 亚洲人与动物交配视频| 国产av码专区亚洲av| 久久韩国三级中文字幕| 91精品一卡2卡3卡4卡| 99热网站在线观看| 亚洲成人一二三区av| 国产免费福利视频在线观看| 亚洲,一卡二卡三卡| 久热这里只有精品99| 视频区图区小说| 一级黄片播放器| 中文天堂在线官网| 简卡轻食公司| 伊人亚洲综合成人网| 国产老妇伦熟女老妇高清| 日本-黄色视频高清免费观看| 亚洲,一卡二卡三卡| 久久女婷五月综合色啪小说| 国产免费一区二区三区四区乱码| 大陆偷拍与自拍| 久久国产亚洲av麻豆专区| 成年人免费黄色播放视频| xxxhd国产人妻xxx| 18+在线观看网站| 有码 亚洲区| 国产高清三级在线| 日韩精品有码人妻一区| 国产精品一区www在线观看| 永久免费av网站大全| 一级毛片我不卡| 日韩熟女老妇一区二区性免费视频| 99九九线精品视频在线观看视频| 国产探花极品一区二区| 色婷婷久久久亚洲欧美| 五月伊人婷婷丁香| 日本欧美视频一区| 一区二区三区四区激情视频| 91久久精品电影网| 蜜桃久久精品国产亚洲av| 女人精品久久久久毛片| 亚洲欧美色中文字幕在线| 99久久中文字幕三级久久日本| 老熟女久久久| 亚洲欧洲国产日韩| 蜜桃久久精品国产亚洲av| 亚洲美女黄色视频免费看| 国产日韩欧美视频二区| 久久99一区二区三区| 国产在视频线精品| 天堂中文最新版在线下载| 老司机亚洲免费影院| 寂寞人妻少妇视频99o| 男人爽女人下面视频在线观看| 永久免费av网站大全| 国产精品99久久99久久久不卡 | 一边摸一边做爽爽视频免费| 99久久中文字幕三级久久日本| 欧美+日韩+精品| 在线 av 中文字幕| 视频区图区小说| 18+在线观看网站| 日韩免费高清中文字幕av| 午夜av观看不卡| 日韩精品免费视频一区二区三区 | 欧美日韩av久久| 日本wwww免费看| 欧美激情 高清一区二区三区| 卡戴珊不雅视频在线播放| 你懂的网址亚洲精品在线观看| 色婷婷久久久亚洲欧美| 成人毛片a级毛片在线播放| 简卡轻食公司| 视频在线观看一区二区三区| 热re99久久精品国产66热6| 少妇丰满av| 国产高清三级在线| 国国产精品蜜臀av免费| 人人妻人人爽人人添夜夜欢视频| xxxhd国产人妻xxx| 国产成人精品福利久久| videossex国产| 欧美三级亚洲精品| 亚洲四区av| 国产黄片视频在线免费观看| 欧美日本中文国产一区发布| 久久韩国三级中文字幕| 色网站视频免费| 99久久精品国产国产毛片| 大话2 男鬼变身卡| 欧美xxxx性猛交bbbb| 国产精品成人在线| 女的被弄到高潮叫床怎么办| 日韩伦理黄色片| 亚洲图色成人| 亚洲一级一片aⅴ在线观看| 在线观看免费视频网站a站| 一级二级三级毛片免费看| 亚洲av二区三区四区| 一级毛片我不卡| 伊人亚洲综合成人网| 日本黄色片子视频| 草草在线视频免费看| 国产高清三级在线| 九色成人免费人妻av| kizo精华| 午夜免费鲁丝| 波野结衣二区三区在线| 婷婷色综合www| 人成视频在线观看免费观看| 热re99久久精品国产66热6|