图  1  太阳风与彗星相互作用示意图（修改自Cravens, 2002）

Figure  1.  Schematic of the interaction of solar wind and a comet (modified from Cravens, 2002)

图  2  探测器Giotto在距离哈雷彗星$ 1.7\times {10}^{6} $ km处，测量的质子的相空间分布. 图中等值线的数值单位为$ \mathrm{c}{\mathrm{m}}^{-3}\mathrm{k}{\mathrm{m}}^{-3}{\mathrm{s}}^{3} $，蓝线为以（0, 0）为圆心的弧，红线为以（−$ {V}_{\mathrm{A}} $, 0）为圆心的弧，其中V_A是阿尔芬速度. 黑色圆圈标记为拾起离子的理论位置（修改自Neugebauer et al., 1989）

Figure  2.  Proton phase space density measured by the spacecraft Giotto with a distance of $ 1.7\times {10}^{6} $ km from the nucleus of Halley's comet (modified from Neugebauer et al., 1989). The unit of phase space density is $ \mathrm{c}{\mathrm{m}}^{-3}\mathrm{k}{\mathrm{m}}^{-3}{\mathrm{s}}^{3} $. The blue dashed line represents a surface of constant speed centered on (0, 0). The red dotted line represents a surface of constant speed centered on (−$ {V}_{A} $, 0), and $ {V}_{\mathrm{A}} $ represents the Alfvén speed. The black circle represents the expected location of pickup ions

图  3  低活动彗星与太阳风相互作用示意图（修改自Glassmeier, 2017）

Figure  3.  Schematic of the interaction between a low-activity comet and solar wind (modified from Glassmeier, 2017)

图  4  Rosetta对彗星67P/C-G附近时间平均的离子通量测量结果，时间范围为2015-01-23 19:00—20:00, 彗星67P/C-G距离太阳约2.5 AU（修改自Broiles et al., 2015）

Figure  4.  Time-averaged ion flux measured by Rosetta on January 23, 2015 19:00–20:00. The distance between 67P/C-G and the sun is around 2.5 AU (modified from Broiles et al., 2015)

图  5  彗星与太阳风相互作用过程中磁场配置（修改自Koenders et al., 2016）. 橙色线为磁力线. （a）太阳风与强活动性彗星的相互作用；（b）太阳风与弱活动性彗星的相互作用

Figure  5.  Magnetic configuration during the interaction of a comet and solar wind (modified from Koenders et al., 2016). The orange line represents the magnetic field line. (a) Interaction between a strongly active comet and solar wind; (b) Interaction between a weakly or intermediately active comet and solar wind

图  6  彗星67P/C-G通过近日点后测量到的磁场的功率谱密度（修改自Glassmeier, 2017）

Figure  6.  Power spectrum density of the magnetic field after comet 67P/C-G passed the perihelion (modified from Glassmeier, 2017)

图  7  日冕中掠日彗星C/2011 W3（Lovejoy）在近日点附近的彗尾形态（修改自Downs et al., 2013）

Figure  7.  The tail of Comet Lovejoy near its perihelion in the corona (modified from Downs et al., 2013)

图  8  根据日冕的磁场和太阳风模拟计算得到的彗尾O⁵⁺离子的运动轨迹. 黄色线为彗星Lovejoy的轨道，蓝色线为日冕中的磁力线，红线为O⁵⁺离子的运动轨迹（修改自Hou et al., 2021）

Figure  8.  Trajectory of O⁵⁺ calculated from the simulation data of the magnetic field and solar wind in the corona (modified from Hou et al., 2021). The yellow line represents the orbit of comet Lovejoy. The blue lines represent the magnetic field line in the corona. The red lines represent the trajectory of O⁵⁺

图  9  太阳风与彗星相互作用中的物理量分布（修改自Ogino et al., 1988）.（a）质量密度的等值线; （b）压力的等值线，箭头表示速度矢量

Figure  9.  Distribution of physical quantities during the interaction of the solar wind and comet Halley (modified from Ogino et al., 1988). (a) Contour of mass density; (b) Contour of pressure. Arrows represent the velocity vector

图  10  不同日心距离下彗星67P/C-G与太阳风相互作用的模拟（修改自Rubin et al., 2015）. 太阳风沿着−x方向. 对流电场沿着−z方向. 图中颜色为太阳风的质量密度，左右两列为不同的视角

Figure  10.  Simulation of the interaction of comet 67P/C-G with the solar wind at different heliocentric distances (modified from Rubin et al., 2015). The solar wind is along the −x direction. The convectional electric field is along the −z direction. The colors in the figure represent the mass density of the solar wind and the left and right columns are different views

图  11  不同质量损失率下掠日彗星对太阳风速度的影响模拟（修改自Rasca et al., 2014）.（a）质量损失率为$ 1.7\times {10}^{4} $ kg/s；（b）质量损失率为$ 1.7\times {10}^{5} $ kg/s. t_c=0表示彗星通过近日点

Figure  11.  Simulation of the influence of the sun-grazing comet on solar wind speed (modified from Rasca et al., 2014). (a) Mass loss rate of $ 1.7\times {10}^{4} $ kg/s; (b) Mass loss rates of $ 1.7\times {10}^{5} $ kg/s. t_c = 0 for a comet passing the perihelion

图  12  太阳风与弱活动性彗星相互作用过程中密度分布模拟（修改自Deca et al., 2017）

Figure  12.  Simulation of the density distribution during the interaction of the solar wind with a weakly active comet (modified from Deca et al., 2017)

图  13  2019年9月2日09:47，模拟在三种不同程度活动性下，彗星322P/SOHO对太阳风速度的影响. （a）低活动性；（b）中活动性；（c）高活动性（修改自He et al., 2021）

Figure  13.  Distribution of the disturbed/undisturbed velocity (unit: km·s⁻¹) for the three different levels of activities of comet 322P/SOHO . (a) low, (b) intermediate, (c) high at 09:47 UT on September 2, 2019 (modified from He et al., 2021)

图  14  在PSP与彗星322P/SOHO相遇时，沿着PSP轨迹对模拟的采样结果（修改自He et al., 2021）.（a）密度;（b）速度;（c）径向磁场分量;（d）热压

Figure  14.  Samples along the PSP trajectory during its encounter with comet 322P/SOHO (modified from He et al., 2021). (a) Density; (b) Velocity; (c) Radial magnetic field component; (d) Thermal pressure