论文标题
自我磨光磁盘的暴力放松形成螺旋结构
Formation of spiral structure from the violent relaxation of self-gravitating disks
论文作者
论文摘要
我们介绍了在暴力放松的背景下螺旋结构形成的数值研究。初始条件是刚性旋转中自磨颗粒的不平衡磁盘。通过该机制，可以在几个自由下降的时间内通过崩溃后的质量喷射来形成稳健和非平稳的螺旋臂。仔细观察，我们发现了与初始配置有关的武器的不同属性。只要磁盘很薄，绕组程度倾向于随着初始角速度而增加。如果圆盘表面是圆形的，则臂的数量和位置均由泊松密度波动来控制，这些泊松密度波动会在引入更多颗粒时产生更多的臂。相反，如果施加了表面椭圆，则有效控制了武器的数量及其位置。否则，厚度的增加会导致复杂的结果，因为手臂和绕组程度的控制程度较小。我们推测，这种复杂性是由强烈的非轴对称场引起的，在剧烈的松弛过程中，这种复杂性破坏了发生前的运动和颗粒的浓度。
We present the numerical study of the formation of spiral structure in the context of violent relaxation. Initial conditions are the out-of-equilibrium disks of self-gravitating particles in rigid rotation. By that mechanism, robust and non-stationary spiral arms can be formed within a few free-fall times by the shearing of the mass ejection following the collapse. With a closer look, we find different properties of the arms in connection with the initial configuration. The winding degree tends to increase with initial angular speed provided that a disk is thin. If disk surface is circular, both number and position of arms are governed by the Poissonian density fluctuations that produce more arms as more particles are introduced. On the contrary, if the surface ellipticity is imposed, the number of arms and their placement are effectively controlled. Otherwise, the increase of thickness leads to a complicated outcome since the number of arms and winding degree are less effectively controlled. We speculate that this complexity is caused by a strong non-axisymmetric field during the violent relaxation that disorganizes the pre-collapse motion and the concentration of particles.
