RUI: Theoretical Studies of Astrophysical Jets Using 1-D and2-D analytic Models

摘要AST-9318745 KOUPELIS，Theodoros将建立一个星系外流(喷流)的二维解析模型。它将部分用于首先求出描述流动的磁流体(MHD)方程的运动积分的方法。一维解析模型的开发将完成，在该模型中，理想的MHD方程组被投影到喷流轴上(窄喷流模型)。利用这些模型，将研究不同物理机制对各种天体物体流出的准直和持续加速的相对重要性。该项目的第一个目标是找出喷流起始处物理参数值的允许范围(例如，磁场强度、密度等)。使外流成为可能，并研究其在靠近源头的物理条件不断变化时的演变。目标是利用观测到的沿喷流长度的流出所提供的信息，研究喷流原点区域的物理性质。第二个目标是研究外流周围介质中不同的压力分布和磁场强度对其准直和演化的影响。目的是研究不同环境下出流的传播和稳定特性。使用感兴趣的参数的适当值或特定外流和环境的观测结果施加的限制，理论结果将与数值模拟以及活动核、中子星和ProStars的外流进行比较。***

ABSTRACT AST-9318745 KOUPELIS, Theodoros A two-dimensional analytic model for outflows (jets) in galaxies will be developed. It will be used in part on the approach of first finding the integrals of motion of the magnetohydrodynamic (MHD) equations describing the flow. The development of a one-dimensional analytic model in which the system of the ideal MHD equations is projected onto the jet axis (the narrow-jet model) will be completed. Using these models an investigation of the relative importance of different physical mechanisms on the collimation and continuous acceleration of outflows from a variety of astrophysical objects will be conducted. The first objective of this project is to find the allowed ranges of values of the physical parameters at the jet origin (e.g., magnetic field strength, density, etc.) for an outflow to be possible, and to study its evolution as the physical conditions close to its source change continuously. The goal is to study the physics of the regions at the origin of jets by using the information provided by observations of the outflow along its length. The second objective is to examine the effects of different pressure distributions and magnetic field strengths in the medium surrounding the outflow on its collimation and evolution. The goal is to study the propagation and stability properties of outflows in different environments. Using appropriate values for the parameters of interest or, when available, the limits imposed by the observations of specific outflows and the environments, the theoretical results will be compared with numerical simulations, and with outflows from active nuclei, neutron stars, and prostars. ***