AI 中文总结
研究快速和慢速日冕物质抛射的三维不对称扩展及角宽度演化，用渐变圆柱壳模型发现二者演化不同，不对称扩展限制全冰淇淋锥模型准确性，强调估计不同方向及高度的角宽度和扩展速度对捕捉其完整物理演化的重要性。
AI 中文摘要
日冕物质抛射（CMEs）的径向和横向尺寸影响其持续时间和在地球相遇的概率。这些特性与CMEs在不同径向和横向方向的扩展速度有关，但大多数早期研究用投影全冰淇淋锥几何模型来模拟CMEs演化，未区分径向和横向扩展。本研究利用渐变圆柱壳模型研究了七个快速和七个慢速CMEs在日冕仪高度内的不对称扩展和运动学。研究证实CMEs不对称扩展，横向扩展超过径向扩展，这种不对称限制了全冰淇淋锥模型的准确性。对于快速和慢速CMEs，前沿速度越高，扩展速度越高。在10 Rs高度，慢速CMEs扩展速度越大，角宽度越大，而快速CMEs横向扩展速度与正面角宽度呈负相关。慢速CMEs的扩展和传播速度呈现两阶段演化，快速CMEs则呈现更多样化趋势。总体而言，快速和慢速CMEs演化不同，在统计估计其物理参数时不应视为单一群体。本研究强调了估计CMEs沿不同方向和超出标准日冕仪高度的角宽度和扩展速度以捕捉其完整物理演化的重要性。
英文摘要
The radial and lateral dimensions of coronal mass ejections (CMEs) influence their duration and probability of encounter at Earth. These properties are linked to the expansion speed of CMEs in different radial and lateral directions; however, most earlier studies modeled CME evolution using a projected full ice-cream cone geometry, which does not distinguish between radial and lateral expansion. Our study investigates the asymmetric expansion (relative radial and lateral components) and kinematics of seven fast and seven slow CMEs within coronagraphic heights, using the Graduated Cylindrical Shell model. Our study confirms that CMEs expand asymmetrically, with lateral expansion exceeding radial expansion in both CME populations. This asymmetry limits the accuracy of the full ice-cream cone model. For both fast and slow CMEs, higher leading edge speeds are associated with higher expansion speeds. At a height of 10 Rs, slow CMEs with larger expansion speeds (lateral and radial) have larger angular widths (face-on and edge-on), whereas fast CMEs exhibit a negative correlation between lateral expansion speed and face-on angular width. We find that the expansion and propagation speeds of slow CMEs exhibit a two-phase evolution, whereas those of fast CMEs display more diverse trends. Overall, this study suggests that fast and slow CMEs evolve differently and should not be treated as a single population in statistical estimates of their physical parameters. Our study highlights the importance of estimating CME angular widths and expansion speeds along different directions, and beyond standard coronagraphic heights, to capture their complete physical evolution.
Comments23 pages, 7 figures, 3 tables; Accepted for publication in ApJ
