• <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 ?

    Microwave preionization and electron cyclotron resonance plasma current startup in the EXL-50 spherical tokamak

    2022-02-15 11:08:02BinCHEN陳彬YubaoZHU朱玉寶QingZHOU周慶JiangboDING丁江波XianmingSONG宋顯明ShaodongSONG宋紹棟YuanmingYANG楊圓明XinZHAO趙鑫EnwuYANG楊恩武MinshengLIU劉敏勝andtheEXL50Team玄龍50團(tuán)隊
    Plasma Science and Technology 2022年1期
    關(guān)鍵詞:陳彬江波

    Bin CHEN (陳彬), Yubao ZHU (朱玉寶), Qing ZHOU (周慶),Jiangbo DING (丁江波), Xianming SONG (宋顯明), Shaodong SONG(宋紹棟), Yuanming YANG (楊圓明), Xin ZHAO (趙鑫), Enwu YANG(楊恩武), Minsheng LIU (劉敏勝) and the EXL-50 Team (玄龍-50團(tuán)隊)

    1 Hebei Key Laboratory of Compact Fusion, Langfang 065001, People’s Republic of China

    2 ENN Science and Technology Development Co., Ltd, Langfang 065001, People’s Republic of China

    Abstract Preionization has been widely employed to create initial plasma and help the toroidal plasma current formation.This research focuses on implementing a simple, economical and practical electron cyclotron resonance (ECR) preionization technique on the newly constructed EXL-50 spherical tokamak, and evaluating the effectiveness on improving the plasma current startup.Two types ECR microwave preionization experiments for the plasma initialization without the central solenoid are reported: (1) 2.45 GHz microwave preionization and current startup with 2.45 GHz ECR source; (2) 2.45 GHz microwave preionization and current startup with 28 GHz ECR source.Application of the 2.45 GHz ECR microwave preionization to the experiments has contributed to(1)getting rid of the plasma breakdown delay;(2)the significant improvement of the discharge quality: the discharge is much longer and more stable while the driven plasma current is larger, compared to the discharge without preionization.

    Keywords: preionization, microwave, ECR, spherical tokamak, plasma current startup

    1.Introduction

    The spherical tokamak(ST)is an attractive option for achieving controlled nuclear fusion with high beta [1–3].However, the ohmic current carrying capability of conventional ST is very limited due to the smaller central pole space.Electron cyclotron resonance(ECR)plasma current startup is important for compact fusion scenarios and future steady state ST reactor operation.

    The EXL-50 is a middle size ST without central solenoid developed in the ENN Group, China [4, 5].One important motivation of the EXL-50 ST is to explore the practicability and validity of ECR plasma current startup.Beyond that,because of the compactness,flexibility and low operation cost,the EXL-50 may contribute to better understanding of phenomena in a wide field such as ST plasma confinement, equilibrium and stability,scenarios of plasma heating and current drive,and development of novel plasma diagnostics etc.

    The initial stage of a ST discharge may be divided into three phases: breakdown, plasma formation and current ramp-up.As regard to the discharge initiation,preionization is considered to be a powerful technique.The conventional thermionic electron emission method of preionization with a tungsten filament depends on the ramp up time of the vertical magnetic field, and impurities from the filament cannot be avoided.This causes difficulties in reliable and reproducible experiment operation.In recent years,microwave applications on fusion plasma devices have become more favorable in the area of preionization and current startup, by producing a target plasma for subsequent plasma heating and current drive.

    Figure 1.Schematic diagram of EXL-50 spherical tokamak.(a) Access ports, available diagnostics, ECRH system and microwave oven arrangement,(b)the poloidal geometry of magnetic field coils and MHD equilibrium magnetic flux surfaces.The last closed flux surface is shown in red, in subplot (b).

    In addition,the microwave preionization can improve the quality of the plasma and discharge.Since 1980s,a number of microwave preionization experiments have been practically demonstrated on the SUNIST [6], TST-2 [7, 8], NSTX[9, 10], VEST [11, 12], QUEST [13], START [14] and MAST [14] STs and SINP [15], T-10 [16], Tore Supra [17],KSTAR [18, 19], Taban [20], HT-6B [21], DIII-D [22–24],GLAST [25], Aditya [26], KAIST [27] and JT-60 [28, 29]tokamaks.For inductive plasma current startup, the ECR preionization is known to be very effective for minimizing the loop voltage.The results from JT-60U [28], DIII-D [22–24],KSTAR [18], T-10 [16], HT-6B [21], and Tore Supra [17]experiments fully prove that ECR preionization plays an important role in reducing the ohmic flux consumption.

    To pursue the ECR plasma experiments on the EXL-50,the lack of central solenoid makes the breakdown and current drive more challenging.According to the EXL-50 initial experimental results, the delayed breakdown happens frequently and startup failure is observed occasionally when operating without the preionization.In order to satisfy the requirements of discharge initiation and quality improvement, the behavior and characteristics of preionization for the EXL-50 need to be carefully studied.

    The 2.45 GHz microwave based preionization startup experiments are presented in this article.The experimental setup is described in section 2.Result and discussion on preionization behaviors with different experimental conditions are described in section 3, which is followed by a conclusion and future plan section.

    2.Experimental setup

    2.1.The EXL-50 apparatus

    The EXL-50 is based on a stainless steel 316 vacuum vessel(3.31 m diameter,2.81 m height)with major radius R ~ 0.58 m and minor radius a ~ 0.33 m.As shown in figure 1, a cylinder of 0.34 m diameter forms the central rod.The magnet system consists of 12 toroidal field (TF) coils and 3 pairs of poloidal field(PF1–PF6)coils.The designed maximum plasma current isIp~500 kA,Bt~0.46 T.The planed auxiliary heating system includes 2.4 MW/28 GHz ECR and 1.0 MW/2.45 GHz low hybrid wave, when toroidal field coils are operated at designed 100 kA current.

    Figure 1 also shows the installed diagnostics on the EXL-50 at the time of this research.One high-speed video camera is used to monitor the visible image of the plasma.One Langmuir probe is installed to measure the edge plasma parameters.The line-integrated density is estimated by a single-channel microwave interferometer.The visible spectrometer is developed to measure the impurities of B,C,Fe, O etc.The intensities of two-channelαHspectral lines are monitored during the ionization process.

    2.2.Microwave systems

    Low power, 2.45 GHz ECR sources are employed for preionization in the EXL-50 1st-phase experiment at ~800 Gauss Bt.Similar 2.45 GHz microwave preionization sources have been frequently used for the ECR assisted plasma startup in several tokamaks,e.g.KAIST[27]and SUNIST[6].Based on the differences of the methods to generate the 2.45 GHz microwave for preionization, two experimental settings for different research purposes are designed.In the first experiment, a 0.75 kW/2.45 GHz household microwave oven is used as the preionization source while a 15 kW/2.45 GHz ECR magnetron drives the current.In the second experiment,a 15 kW/2.45 GHz ECR magnetron was used as the preionization source (maximum power of ~12 kW was injected into the vacuum vessel which was measured by the water load),while a 50 kW/28 GHz ECR gyrotron was employed to drive the toroidal current.

    Figure 2.The radial position of the ECR fundamental frequency resonance layer RECR versus TF coil current IT F.The blue line is for 28 GHz microwave,the red line is for 2.45 GHz microwave,the grey shadow is the central rod (R = 0.17 m), the magenta shadow is the limiter (R = 1.53 m), the area in between is the vacuum vessel.

    The present EXL-50 ECR systems include one 50 kW/28 GHz gyrotron and three 15 kW/2.45 GHz magnetrons.The ECR and microwave oven arrangement on EXL-50 is shown in figure 1.The modified 2.45 GHz/0.75 kW household microwave oven is installed at the 30° window.It is temporarily installed for prototype testing and replaced by ECRH 2# (# means number, see figure 1) after the microwave oven preionization experiment.The 2.45 GHz/15 kW/CW (continuous wave) ECR systems are installed at the windows:270°,30°,and 300°for the ECRH 1#,2#and 3#magnetrons, respectively.The gyrotron 28 GHz/50 kW/30 s ECRH is installed at the 0° window.The low field side ECR antennas arrangement allows extensive control of toroidal injection angles by adjustable mirrors.Twisted waveguide is used to control the polarization of the 2.45 GHz ECR wave which allows O-mode or X-mode power injection for all injection angles.

    As the microwave source frequency is fixed,the position of the fundamental frequency resonance layer varies only depending on the TF coils currentITFwhich determines the toroidal magnetic field BT.For the maximum safe current in the TF coils (100 kA), the BTin the center of the vessel is about 0.4 T.However, theITFmay change for different physics experiment purposes.In the two 2.45 GHz ECR sources experiment, theITFis kept constant around 16 kA.While, in the 2.45 GHz microwave preionization and current startup with 28 GHz ECR source experiment, theITFis set to climb from 16 kA to 90 kA during the discharges, which gives different positions of the resonance layers.In figure 1 subplot (a), the fundamental frequency resonance layers,where the preionization is expected to be observed, are displayed.For 28 GHz ECR, the resonance layer is located at R = 0.24 m, as theITF=100 kA (magenta, dash line).For 2.45 GHz ECR, the resonance layers are located at R = 0.44 m, as theITF=16 kA (red, dash line), and at R = 1.53 m, as theITF=56 kA (blue, dash line), respectively.In figure 2,the radial position of the ECR fundamental frequency resonance layerRECRversus TF coil currentITFis shown.The blue line is for 28 GHz microwave,while the red line is for 2.45 GHz microwave.The 2.45 GHz fundamental frequency resonance layer moves out of the vacuum vessel as theITF>56 kA,while the 28 GHz moves into the vessel as theITF>74 kA.

    3.Experiments and preliminary results

    3.1.Microwave preionization and current startup with two 2.45 GHz ECR sources

    In the microwave oven preionization experiment, the 2.45 GHz wave from a modified household microwave oven with power level of 0.75 kW is used as the preionization source, which is kept injected from the low field side midplane during the entire process of the experiment.While the 2.45 GHz magnetron with power up to 15 kW (continuous wave), which operates as the ECRH/CD system, is injected at 0 s.

    Before the formal experiment, a test experiment is conducted with only the microwave oven source is turned on without the 15 kW ECRH/CD power injected.The test result of shot #1351 is shown in figure 3.The preionization is clearly captured by the high-speed camera (figure 3(e)).According to the theoretical calculation, for 2.45 GHz microwave,the preionization ought to be located at the major radius R = 0.44 m as theITF=16 kA.Figure 3(e)shows that a bright cylindrical tube with a certain broadening in width occurs and holds there around the ECRH fundamental frequency resonance layer.The preionization is typically timed to start at the initial stage for a discharge, when the EXL-50 plasma electron temperature and vacuum pressure are low at several eV and 10?4Palevel, respectively.Under such parameters, the ionization is always accompanied with obvious visible light emission, which could be observed by the visible camera.

    Another evidence to prove the preionization’s success is the observed toroidal current (for convenience the toroidal current before the closed flux surface formation is named asIpas well) and chord integrated electron density signal in figures 3(a) and (b).Although, no closed flux surface is generated in shot #1351, the 750 W microwave still drives 450 A toroidal current.The measured electron density signal(~1 .2 × 1016m?2)implies that a sufficient number of neutral gas is ionized.The gas is injected before 0 s and at 7 s,respectively.The first increase of the density is accompanied with the current jump near 3 s when the breakdown triggered even though the produced plasma line-averaged density was low,at ~1 .2 × 1016m?2level.The gradual drop in density is due to the consumption of the injected gas and continuously pumping.When the gas is injected again at 7 s, the density increases again.According to the poloidal field coil current signal(figure 3(d),the currents in all of the PF coils are set to the same waveform for shot#1351),we can confirm that the toroidal current is driven purely by the preionization microwave,not the ohmic drive from PF.After 12 s the PF currents declining steadily,although the ohmic driven current changes sign, the toroidal current keeps stable and unchanged.

    Figure 3.Experimental signals (a) toroidal current, (b) chord-integrated electron density, (c) gas injection at ?1.9 s (not shown) and 7 s,(d) PF3 coil current and (e) the high-speed Phantom camera image at 3 s for the shot 1351 of EXL-50.The microwave, from a modified household microwave oven with power level of 0.75 kW,was kept injected from the low field side midplane all the way until the end of this discharge.No other ECR power was injected for this shot.

    The preliminary test results of shot #1351 have proved that the microwave oven preionization is effective.The following formal experiments are designed and conducted to investigate how the preionization impacts on the parameters and quality of the EXL-50 discharges.

    In these experiments, discharges with and without microwave preionization are compared in table 1 and figure 4.For the comparability, the pre-set waveforms and settings of the controllable parameters are kept the same to guarantee the univariate experimental conditions.For the ECRH power scan experiments,the only difference in experimental settings is whether there is preionization (PMicrowave=0.75 kW) or not (PMicrowave=0 kW).Table 1 shows the statistic results.Note that for O-mode with 5 kW ECRH power,the discharge waveforms are almost the same.However,the shot duration is shorter for the case without preionization (4.8 s/4.9 s) than that with preionization(8.0 s/8.1 s).In general,the shots with preionization show a significantly longer plasma duration(>30%) with a higher plasma current (Ip, > 10%, for example, see 8 kW cases in figure 4) than the cases without preionization, which implies that the quality of the discharges is improved by the microwave preionization.Microwave preionization generally helps the discharges to be more stable and longer, and improving theIpas well.

    3.2.2.45 GHz microwave preionization and current startup with 28 GHz ECR source

    In the experiment, the 2.45 GHz magnetron ECR with power up to 15 kW is used as the preionization source, which is injected from the low field side midplane at ?2 s.Then the 28 GHz gyrotron ECRH/CD system with power up to 50 kW(pulse length of 30 s) is injected at 0 s.The 2.45 GHz preionization source is switched off after the injection of 28 GHz ECRH.

    Figure 4.Comparison of waveforms for 8 kW ECRH discharges with and without preionization.(a) Plasma current Ip , (b) chordin tegrated electron density n e.For each kind of ECR mode injection experiments,cases with the 0.75 kW microwave preionization(dash curves) and without preionization (solid curves) are compared.

    Figure 5.Experimental signals and the preionization image at ?0.500, ?0.455, ?0.419 and ?0.371 s for the shot #4984 of EXL-50.The waveforms on the right is the zoom-in of the left subplot between ?0.8 and ?0.2 s.(a) Plasma current, (b) electron density, (c) TF coils current,(d)PF1 coil current,(e)PF3 coil current and(f)PF5 coil current.The magnetron 2.45 GHz ECR system is used as the preionization source, which is injected from ?2 to 0 s.The 28 GHz ECRH system is injected at 0 s, and after the 2.45 GHz preionization source is switched off.

    Table 1.ECRH power scan of shot duration with and without preionization by the injection of 0.75 kW microwave power.A magnetron of 2.45 GHz ECR with O-mode or X-mode was turned on at 0 s and turned off at 12 s for all the shots.The waveforms for 8 kW discharges with O-/X-mode are shown in figure 4 as an example.

    In order to obtain high parameter plasmas, the capability of toroidal magnetic fieldBTis increased to 100 kA level,leading to the upgrade of the ECR system.As a result, the main ECR frequency has been changed from 2.45 to 28 GHz.For the 28 GHz discharges,the flat top ofITFhas to be larger than 71 kA to guarantee that the ECRH fundamental frequency resonance layer lies inside the vacuum vessel.However, for the 2.45 GHz preionization, the limitation forITFis in between 6.2 and 56 kA (figure 2).So, to include the 2.45 GHz preionization in a 28 GHz ECRH/CD discharge,the waveform ofITFshould climb from a lower value (e.g.15 kA in shot #4984) to around 90 kA, as shown in figure 5(magenta curve).In shot 4984, the 2.45 GHz ECR preionization power is injected from ?2 to 0 s.In this period,the preionization image evolving with the rising of theITFis observed.Before ?0.5 s when theITFis low (15 kA), a clear bright cylindrical tube is generated by the preionization process right at the ECR fundamental frequency resonance layer near the central rod.Then the preionization region moves outward with the rising of theITF,and moves out of the vacuum vessel after ?0.371 s.The key goal, no delayed breakdown,of this experiment is accomplished(that is to say,the plasma current and density quickly climb at 0 s),which is extremely important for the plasma control and experiment operation.

    4.Conclusion and future plan

    In summary, microwave preionization in the EXL-50 has been proven robust,the ordinary discharge waveforms can be obtained as long as the ECR fundamental frequency resonance layer is located inside the torus.It was observed that with the help of microwave preionization, the plasma current could be started up with no delayed breakdown, it can be sustained by the main ECR/CD after 0 s and the discharge quality is improved obviously: the discharge is much longer and more stable compared to the discharge without ECR preionization, and the driven plasma current is larger.

    These initial results are promising for using ECR as preionization source as well as heating and current driving source in a future ST reactor.The 28 GHz preionization is preferable, when theITFis raised to 100 kA level.Further work is needed to demonstrate that the low microwave power,as a 28 GHz preionization source, can help improve the electron cyclotron plasma current startup without the central solenoid for a high power ECRH system and in a much higher parameter interval.

    Acknowledgments

    This work was funded by the compact fusion project in the ENN group.The authors would like to appreciate Dr Y-K M Peng and B S Yuan for supports on the EXL-50 physics and engineering,Dr H Y Guo for invaluable comments,S J Li for providing the density data, and Y Liu for help running the experiments.

    ORCID iDs

    猜你喜歡
    陳彬江波
    Variational quantum eigensolvers by variance minimization
    本期作者介紹
    努力做一件事的樂趣
    Controllable four-wave mixing response in a dual-cavity hybrid optomechanical system*
    Peaked Periodic Wave Solutions to the Broer–Kaup Equation?
    江波繪畫作品
    愛到最后
    愛到最后
    短篇小說(2016年8期)2016-09-20 01:20:17
    傻貨
    短篇小說(2014年9期)2014-09-20 15:16:43
    My Story以筆相伴靜書寫
    海外英語(2013年8期)2013-11-22 09:16:04
    亚洲成人国产一区在线观看| 国产精品综合久久久久久久免费 | 久久久久国内视频| 女警被强在线播放| 最近最新中文字幕大全电影3 | 午夜福利视频在线观看免费| 在线十欧美十亚洲十日本专区| 视频区图区小说| 亚洲精品美女久久av网站| 好看av亚洲va欧美ⅴa在| 亚洲欧美激情综合另类| 午夜福利视频在线观看免费| www.自偷自拍.com| 女人久久www免费人成看片| 91国产中文字幕| 久久久国产一区二区| 女人爽到高潮嗷嗷叫在线视频| 亚洲欧美精品综合一区二区三区| 精品卡一卡二卡四卡免费| 久久久久国产一级毛片高清牌| 国产又爽黄色视频| 身体一侧抽搐| 国产精品国产高清国产av | 亚洲成av片中文字幕在线观看| 日韩人妻精品一区2区三区| 女人精品久久久久毛片| 成人永久免费在线观看视频| tube8黄色片| 国产三级黄色录像| 国产午夜精品久久久久久| 欧美黑人精品巨大| 亚洲欧洲精品一区二区精品久久久| 国产精品一区二区在线观看99| 久久亚洲精品不卡| 免费高清在线观看日韩| 成人国语在线视频| 757午夜福利合集在线观看| 波多野结衣av一区二区av| 国产精品一区二区在线观看99| 久久午夜亚洲精品久久| 国产麻豆69| 高清毛片免费观看视频网站 | 亚洲成国产人片在线观看| 欧美日韩亚洲综合一区二区三区_| 午夜福利,免费看| 亚洲第一av免费看| 黄色成人免费大全| 我的亚洲天堂| 欧美大码av| 99热网站在线观看| 亚洲性夜色夜夜综合| 国产成人系列免费观看| 手机成人av网站| 国产单亲对白刺激| 叶爱在线成人免费视频播放| 在线观看免费视频网站a站| 91字幕亚洲| 国产精品亚洲一级av第二区| a级毛片黄视频| av天堂久久9| 欧美成狂野欧美在线观看| 久久久久久久精品吃奶| tube8黄色片| 美女国产高潮福利片在线看| 日韩有码中文字幕| 在线观看午夜福利视频| 一级,二级,三级黄色视频| 午夜福利在线免费观看网站| 日本精品一区二区三区蜜桃| 亚洲av成人不卡在线观看播放网| 精品一区二区三区视频在线观看免费 | 麻豆乱淫一区二区| 久久ye,这里只有精品| 亚洲第一欧美日韩一区二区三区| e午夜精品久久久久久久| 黄色片一级片一级黄色片| 一夜夜www| 男女下面插进去视频免费观看| 黑丝袜美女国产一区| 岛国毛片在线播放| 国产欧美亚洲国产| 免费在线观看完整版高清| 99热只有精品国产| 亚洲片人在线观看| 日韩欧美三级三区| 成人免费观看视频高清| 日本vs欧美在线观看视频| 国产激情欧美一区二区| 少妇 在线观看| 中文字幕制服av| 免费黄频网站在线观看国产| 亚洲专区国产一区二区| 在线观看免费高清a一片| 欧美大码av| 国产高清videossex| 欧美人与性动交α欧美精品济南到| 国产av精品麻豆| 在线天堂中文资源库| 久久久精品免费免费高清| a级片在线免费高清观看视频| 一a级毛片在线观看| 国产xxxxx性猛交| 久热这里只有精品99| 国产真人三级小视频在线观看| 少妇粗大呻吟视频| 亚洲专区字幕在线| 欧美中文综合在线视频| 欧美国产精品一级二级三级| 色综合欧美亚洲国产小说| 亚洲欧洲精品一区二区精品久久久| 欧美性长视频在线观看| 久久中文看片网| 久久香蕉激情| 50天的宝宝边吃奶边哭怎么回事| 一本大道久久a久久精品| 亚洲三区欧美一区| 色婷婷久久久亚洲欧美| 变态另类成人亚洲欧美熟女 | 美女高潮喷水抽搐中文字幕| 日韩欧美一区视频在线观看| 国产男靠女视频免费网站| 久久天堂一区二区三区四区| 久久精品aⅴ一区二区三区四区| 亚洲精品久久成人aⅴ小说| 精品人妻在线不人妻| 欧美日本中文国产一区发布| 99精品久久久久人妻精品| 在线国产一区二区在线| 日韩 欧美 亚洲 中文字幕| 亚洲欧美一区二区三区黑人| 免费在线观看黄色视频的| 操出白浆在线播放| 一区在线观看完整版| 丝袜人妻中文字幕| 亚洲人成电影观看| 后天国语完整版免费观看| 欧美日韩视频精品一区| 99热国产这里只有精品6| x7x7x7水蜜桃| 美女 人体艺术 gogo| 久久久国产一区二区| 成年人午夜在线观看视频| 少妇被粗大的猛进出69影院| 三级毛片av免费| 不卡av一区二区三区| 他把我摸到了高潮在线观看| 精品熟女少妇八av免费久了| 在线十欧美十亚洲十日本专区| 亚洲视频免费观看视频| 一级作爱视频免费观看| 欧美中文综合在线视频| 日日爽夜夜爽网站| 又紧又爽又黄一区二区| 国产精品乱码一区二三区的特点 | 精品亚洲成国产av| 老熟妇仑乱视频hdxx| 亚洲第一av免费看| 亚洲精品久久成人aⅴ小说| 午夜福利乱码中文字幕| 免费在线观看完整版高清| 国产av精品麻豆| 中文字幕人妻熟女乱码| 色婷婷av一区二区三区视频| 女警被强在线播放| 国内久久婷婷六月综合欲色啪| 高潮久久久久久久久久久不卡| 亚洲成人手机| 国产精品.久久久| 亚洲黑人精品在线| 国产麻豆69| 中文字幕精品免费在线观看视频| 免费在线观看完整版高清| 久久这里只有精品19| 欧美乱码精品一区二区三区| 国产男靠女视频免费网站| 色94色欧美一区二区| 免费看十八禁软件| 亚洲av成人av| 国产成人精品久久二区二区91| 久久这里只有精品19| 国产精品欧美亚洲77777| 夜夜躁狠狠躁天天躁| 在线观看66精品国产| 国产精品影院久久| 80岁老熟妇乱子伦牲交| 国产在线观看jvid| 高清视频免费观看一区二区| 亚洲av第一区精品v没综合| 国产精品久久久av美女十八| 国产免费av片在线观看野外av| 成人免费观看视频高清| 满18在线观看网站| 在线观看免费日韩欧美大片| x7x7x7水蜜桃| 国产精品免费大片| 精品国内亚洲2022精品成人 | 精品国产国语对白av| 欧美人与性动交α欧美软件| 色婷婷久久久亚洲欧美| 麻豆成人av在线观看| 国产成人欧美| 人人妻,人人澡人人爽秒播| 国产av一区二区精品久久| 久久久久久久午夜电影 | 天堂√8在线中文| 岛国毛片在线播放| 成在线人永久免费视频| 成人av一区二区三区在线看| 91成人精品电影| 午夜免费成人在线视频| 国产欧美日韩一区二区三| 精品国产美女av久久久久小说| www.999成人在线观看| 91成年电影在线观看| 久久人妻福利社区极品人妻图片| 久久久久国内视频| 婷婷丁香在线五月| 脱女人内裤的视频| 757午夜福利合集在线观看| 欧美日韩黄片免| 午夜日韩欧美国产| 一二三四在线观看免费中文在| 中文字幕制服av| 国产野战对白在线观看| 国产精品久久久av美女十八| 欧美精品高潮呻吟av久久| 天天影视国产精品| 日韩免费高清中文字幕av| a级毛片黄视频| av中文乱码字幕在线| 国产精品二区激情视频| 亚洲中文av在线| a级毛片在线看网站| 99热网站在线观看| 国产男女内射视频| 免费观看精品视频网站| 不卡av一区二区三区| 精品一区二区三区视频在线观看免费 | 亚洲国产精品一区二区三区在线| 欧美亚洲 丝袜 人妻 在线| 最新的欧美精品一区二区| 精品无人区乱码1区二区| 看免费av毛片| 热99国产精品久久久久久7| videos熟女内射| 日韩三级视频一区二区三区| 久久精品91无色码中文字幕| 欧美日韩福利视频一区二区| 熟女少妇亚洲综合色aaa.| 国产1区2区3区精品| 久久精品亚洲精品国产色婷小说| 少妇 在线观看| 成人国产一区最新在线观看| 亚洲成人国产一区在线观看| 男女免费视频国产| 极品人妻少妇av视频| 操出白浆在线播放| 精品一区二区三区四区五区乱码| 亚洲精品乱久久久久久| 在线国产一区二区在线| 亚洲全国av大片| 精品亚洲成a人片在线观看| 亚洲精品在线观看二区| 亚洲精品久久成人aⅴ小说| 十八禁网站免费在线| 国产精品 国内视频| www.精华液| 亚洲情色 制服丝袜| 两性午夜刺激爽爽歪歪视频在线观看 | 曰老女人黄片| 亚洲一区中文字幕在线| 一区二区三区激情视频| 国产精品久久久av美女十八| 午夜福利,免费看| 视频在线观看一区二区三区| 国产区一区二久久| 亚洲精品国产一区二区精华液| 免费在线观看视频国产中文字幕亚洲| 亚洲精品在线观看二区| 欧美日韩乱码在线| 三级毛片av免费| 国产99久久九九免费精品| 国产精品国产高清国产av | 亚洲av日韩精品久久久久久密| 99国产综合亚洲精品| 99香蕉大伊视频| 日日爽夜夜爽网站| 精品一区二区三区视频在线观看免费 | 亚洲七黄色美女视频| 一区二区三区精品91| 国产男女内射视频| 91九色精品人成在线观看| 亚洲欧美激情在线| 国产精品国产av在线观看| 露出奶头的视频| 久久性视频一级片| 亚洲免费av在线视频| 成人18禁高潮啪啪吃奶动态图| 久久精品亚洲熟妇少妇任你| 国产深夜福利视频在线观看| 国产av精品麻豆| 国产精品免费大片| 水蜜桃什么品种好| 欧美激情 高清一区二区三区| 国产成人影院久久av| 亚洲精品国产一区二区精华液| 美女福利国产在线| 久久香蕉精品热| 亚洲国产毛片av蜜桃av| 国产精品久久电影中文字幕 | 淫妇啪啪啪对白视频| 麻豆乱淫一区二区| 欧美精品高潮呻吟av久久| 国产精品二区激情视频| 麻豆av在线久日| 欧美中文综合在线视频| 欧美不卡视频在线免费观看 | 视频区图区小说| 午夜日韩欧美国产| 国产xxxxx性猛交| 日韩一卡2卡3卡4卡2021年| 免费在线观看影片大全网站| 俄罗斯特黄特色一大片| 午夜成年电影在线免费观看| 精品少妇一区二区三区视频日本电影| 亚洲久久久国产精品| 在线观看日韩欧美| 91老司机精品| 美女国产高潮福利片在线看| 午夜福利一区二区在线看| 久久性视频一级片| 国产99久久九九免费精品| 亚洲专区中文字幕在线| 露出奶头的视频| 亚洲成国产人片在线观看| 亚洲精品一卡2卡三卡4卡5卡| 男女之事视频高清在线观看| 国产免费男女视频| 狠狠狠狠99中文字幕| 99国产精品99久久久久| 精品一品国产午夜福利视频| 亚洲七黄色美女视频| 夫妻午夜视频| 高清欧美精品videossex| 女人被躁到高潮嗷嗷叫费观| 久热这里只有精品99| 国产成人精品久久二区二区91| 国产在线精品亚洲第一网站| 亚洲精品中文字幕在线视频| 视频区欧美日本亚洲| 男人操女人黄网站| 久久国产亚洲av麻豆专区| 国产又爽黄色视频| 大片电影免费在线观看免费| 人妻 亚洲 视频| 成年女人毛片免费观看观看9 | 久久久国产欧美日韩av| 久久精品成人免费网站| 国产麻豆69| 国产激情欧美一区二区| 999久久久国产精品视频| videosex国产| 国产亚洲欧美98| av免费在线观看网站| 国产男女超爽视频在线观看| av电影中文网址| 叶爱在线成人免费视频播放| 最新美女视频免费是黄的| 日韩制服丝袜自拍偷拍| 黑丝袜美女国产一区| 三级毛片av免费| 午夜福利影视在线免费观看| 国产日韩欧美亚洲二区| 俄罗斯特黄特色一大片| 两人在一起打扑克的视频| 少妇猛男粗大的猛烈进出视频| 精品亚洲成国产av| 国产黄色免费在线视频| 老司机福利观看| 亚洲精品国产区一区二| 大陆偷拍与自拍| 在线观看舔阴道视频| 国产一区二区三区在线臀色熟女 | 中文亚洲av片在线观看爽 | 嫩草影视91久久| 精品熟女少妇八av免费久了| 亚洲精品在线观看二区| 成年女人毛片免费观看观看9 | 大型av网站在线播放| 国产日韩一区二区三区精品不卡| av天堂在线播放| 亚洲久久久国产精品| 后天国语完整版免费观看| 亚洲av片天天在线观看| 亚洲 国产 在线| 久久人妻熟女aⅴ| 中出人妻视频一区二区| 中文亚洲av片在线观看爽 | 高潮久久久久久久久久久不卡| 深夜精品福利| 黄色毛片三级朝国网站| 99国产综合亚洲精品| 亚洲自偷自拍图片 自拍| 欧美日韩乱码在线| 精品福利观看| 交换朋友夫妻互换小说| 在线观看免费高清a一片| 欧美激情 高清一区二区三区| 狂野欧美激情性xxxx| 亚洲欧美日韩另类电影网站| 午夜福利乱码中文字幕| 丝袜人妻中文字幕| 国产精品电影一区二区三区 | 色精品久久人妻99蜜桃| 看黄色毛片网站| 欧美精品高潮呻吟av久久| 久久香蕉激情| 成人精品一区二区免费| 精品视频人人做人人爽| 午夜精品在线福利| 欧美日韩黄片免| 99热国产这里只有精品6| 99久久人妻综合| 超色免费av| a级毛片黄视频| 捣出白浆h1v1| 亚洲成国产人片在线观看| 日本黄色视频三级网站网址 | 国产亚洲欧美精品永久| 又紧又爽又黄一区二区| 天堂√8在线中文| 国产高清videossex| 每晚都被弄得嗷嗷叫到高潮| 一夜夜www| 黄片播放在线免费| 国产精品久久久久久精品古装| 精品国产一区二区三区久久久樱花| 好看av亚洲va欧美ⅴa在| 亚洲国产精品一区二区三区在线| 黑人巨大精品欧美一区二区mp4| 十八禁人妻一区二区| 欧美 日韩 精品 国产| 精品一区二区三区四区五区乱码| 啦啦啦免费观看视频1| 亚洲成国产人片在线观看| 精品电影一区二区在线| 1024视频免费在线观看| 9191精品国产免费久久| 国产精品久久久av美女十八| 亚洲黑人精品在线| 少妇猛男粗大的猛烈进出视频| 午夜福利欧美成人| 超色免费av| 欧美日韩瑟瑟在线播放| 国产精品二区激情视频| 国产精品免费大片| 91成人精品电影| 日韩人妻精品一区2区三区| 我的亚洲天堂| 亚洲国产欧美日韩在线播放| 亚洲精品中文字幕一二三四区| 午夜免费鲁丝| 热99久久久久精品小说推荐| 色婷婷av一区二区三区视频| 国产亚洲精品久久久久久毛片 | 国产精品 欧美亚洲| 男女午夜视频在线观看| 久久久精品国产亚洲av高清涩受| 男人舔女人的私密视频| 精品欧美一区二区三区在线| 国产不卡av网站在线观看| 国产精品电影一区二区三区 | 成人精品一区二区免费| 久久香蕉国产精品| 亚洲情色 制服丝袜| 久久精品熟女亚洲av麻豆精品| 欧美乱妇无乱码| 欧美 亚洲 国产 日韩一| 国产不卡av网站在线观看| 国产精品秋霞免费鲁丝片| 成年人午夜在线观看视频| 黑丝袜美女国产一区| 亚洲综合色网址| 一二三四在线观看免费中文在| 亚洲精品美女久久久久99蜜臀| av片东京热男人的天堂| 激情视频va一区二区三区| 亚洲av欧美aⅴ国产| 亚洲专区字幕在线| 又大又爽又粗| 日韩欧美国产一区二区入口| 欧洲精品卡2卡3卡4卡5卡区| 老汉色av国产亚洲站长工具| 日韩免费高清中文字幕av| 精品国产乱码久久久久久男人| 咕卡用的链子| 久久中文字幕一级| 看免费av毛片| 99国产极品粉嫩在线观看| 亚洲av日韩在线播放| 免费观看精品视频网站| 精品一品国产午夜福利视频| 中出人妻视频一区二区| 国产深夜福利视频在线观看| 中文欧美无线码| 99国产精品一区二区三区| 狠狠婷婷综合久久久久久88av| 国产人伦9x9x在线观看| av在线播放免费不卡| 精品午夜福利视频在线观看一区| 一区二区日韩欧美中文字幕| 国产精品电影一区二区三区 | 人人澡人人妻人| 亚洲成人国产一区在线观看| 成人18禁在线播放| 亚洲av成人不卡在线观看播放网| 欧美精品人与动牲交sv欧美| 国产在线精品亚洲第一网站| 韩国精品一区二区三区| 国产黄色免费在线视频| 国产精品乱码一区二三区的特点 | 一区在线观看完整版| 午夜两性在线视频| 又大又爽又粗| 久热爱精品视频在线9| 精品国产乱码久久久久久男人| 一区二区三区国产精品乱码| 亚洲精品粉嫩美女一区| 欧美中文综合在线视频| 久久精品国产a三级三级三级| 国产成人av教育| 国产99白浆流出| 色精品久久人妻99蜜桃| 欧美人与性动交α欧美软件| 国产一区二区三区综合在线观看| 午夜成年电影在线免费观看| 久久精品aⅴ一区二区三区四区| 后天国语完整版免费观看| 国产精品一区二区精品视频观看| 亚洲男人天堂网一区| 人人澡人人妻人| 99国产精品免费福利视频| 亚洲情色 制服丝袜| 久久精品国产亚洲av香蕉五月 | 欧美精品人与动牲交sv欧美| 国产成人精品久久二区二区免费| 99在线人妻在线中文字幕 | 久久精品熟女亚洲av麻豆精品| 99久久国产精品久久久| 中文字幕制服av| 91国产中文字幕| 亚洲专区国产一区二区| 国产成人精品无人区| 欧美人与性动交α欧美软件| 黄频高清免费视频| 欧美日韩av久久| 久久天躁狠狠躁夜夜2o2o| 麻豆乱淫一区二区| 日韩人妻精品一区2区三区| 久久精品亚洲熟妇少妇任你| 黄色视频,在线免费观看| 亚洲精品av麻豆狂野| 99国产精品免费福利视频| 黄色怎么调成土黄色| avwww免费| 男女高潮啪啪啪动态图| 人妻一区二区av| 在线观看免费高清a一片| 成在线人永久免费视频| 高清欧美精品videossex| 69av精品久久久久久| 王馨瑶露胸无遮挡在线观看| 欧美黄色片欧美黄色片| 国产精品欧美亚洲77777| 国产不卡一卡二| 成人三级做爰电影| 日韩精品免费视频一区二区三区| 夜夜夜夜夜久久久久| 色在线成人网| 精品午夜福利视频在线观看一区| 欧美av亚洲av综合av国产av| aaaaa片日本免费| 韩国精品一区二区三区| 极品人妻少妇av视频| 亚洲av美国av| 亚洲va日本ⅴa欧美va伊人久久| av福利片在线| 精品国产美女av久久久久小说| 国产在视频线精品| a级毛片在线看网站| 国产视频一区二区在线看| 两性夫妻黄色片| 丝瓜视频免费看黄片| 欧美日韩一级在线毛片| 欧美+亚洲+日韩+国产| 免费观看a级毛片全部| 国产高清视频在线播放一区| 精品一区二区三区四区五区乱码| 天天躁狠狠躁夜夜躁狠狠躁| 大片电影免费在线观看免费| 久久狼人影院| 91麻豆av在线| 一进一出好大好爽视频| 国产aⅴ精品一区二区三区波| 99精品欧美一区二区三区四区| 久久人人爽av亚洲精品天堂| 国产成人精品久久二区二区91| 国产深夜福利视频在线观看| 99久久综合精品五月天人人| 黄色女人牲交| 看免费av毛片| 天堂√8在线中文| 少妇猛男粗大的猛烈进出视频| 叶爱在线成人免费视频播放| av不卡在线播放|