Polarization in the Lyman-$\alpha$ line caused by anisotropic electron collisions has been investigated in the Large Helical Device (LHD). High-sensitivity polarization-resolved measurements of the Lyman-$\alpha$ line from edge LHD plasma have been carried out. To obtain spectra of linearly polarized light at all angles a high-reflectivity mirror, a polarization analyzer, and a half-waveplate have been additionally installed into an existing VUV spectrometer system. These optical components have been designed and developed by the CLASP (Chromospheric Lyman-Alpha Spectro-Polarimeter) [R Kano et al. ApJL, 839(1):L10, 2017] team. The present measurement has been made during an electron cyclotron heated discharge. Intensity of the Lyman-$\alpha$ line integrated over line profile has been obtained and plotted as a function of time to generate temporal profile of line. The profile shows that intensity of light varies in synchronization with the angle of the observed linearly polarized light, which clearly indicates that the line is polarized. By performing least-squares fitting on the temporal profile, the magnitude of polarization degree has been evaluated to be 0.033 $\pm$ 0.004. In addition, phase analysis of the measured intensity variation has been carried out. From this analysis it has been found that the observed polarization in Lyman-$\alpha$ can be attributed to the anisotropic electron velocity distribution function (EVDF) at the inboard side of LHD plasma. The preliminary results of a simulation model code suggest that the value of polarization degree is negative and electron temperature in the perpendicular direction to the magnetic field is higher compared to electron temperature in the parallel direction. Therefore, the final value of polarization degree in Lyman-$\alpha$ is $-0.033\pm 0.004$.

莱曼偏振$\alpha$在大型螺旋装置（LHD）中已经研究了由各向异性电子碰撞引起的直线。Lyman-的高灵敏度极化分辨测量$\alpha$从边缘LHD血浆中分离出一条直线。为了获得所有角度的线性偏振光光谱，在现有的VUV光谱仪系统中还额外安装了高反射镜，偏振分析仪和半波片。这些光学组件是由CLASP（Cymosphere Lyman-Alpha Spectro-Polarimeter）设计和开发的[R Kano等。ApJL，839（1）：L10，2017]团队。本测量是在电子回旋加速器加热放电期间进行的。莱曼强度$\alpha$已获得在线轮廓上积分的线，并将其绘制为时间的函数，以生成线的时间轮廓。该轮廓表明光的强度与观察到的线性偏振光的角度同步变化，这清楚地表明该线是偏振的。通过对时间轮廓进行最小二乘拟合，极化度的大小被评估为0.033$\pm$0.004。另外，已经对所测量的强度变化进行了相位分析。通过该分析发现，在莱曼光谱中观察到的极化$\alpha$可以归因于LHD等离子体内侧的各向异性电子速度分布函数（EVDF）。仿真模型代码的初步结果表明，极化度的值为负，并且垂直于磁场的方向的电子温度比平行方向的电子温度高。因此，Lyman-$\alpha$ 是 $-0.033\pm 0.004$。