| dc.description.abstract | In histroy, there are only few people who have very high positive energy, however, they trun the table in critical time. Analoginally, the cosmic rays with the energy density is larger than plasma and magnetic field, it should participate in and influence the evolutin of astronomical enviroments, despite they are rare. This thesis investigates a self-consistent hydrodynamical model, which comprises magnetized thermal plasma, cosmic rays, forward and backward propagating Alfvén waves.
Chapter 1 introduces our four-fluids model, begin from the cosmic ray transport equation, after frames trasformation and includes the relation between scattering frequencies and gwowth rate of Alfvén waves, intergal the momentum, then toward the hydrodynamics model.
In chpater 2, we study the stability of our model and discuss basic linearly and analytically. Prior rsearch indicated there is magneto-acoustic instability driven by cosmic ray and backward Alfvén wave excited by streaming instability. As the result by adding the forward Alfvén wave, the second order Fermi acceleration effect arises in our four-fluid model (i.e. cosmic ray, plasma, forward and backward Alfvén waves), spontaneousness. This cosmic-ray plasma and waves system exchange energy among cosmic ray, plasma and waves via: (1) waves gain energy from self-excite effect by cosmic ray; (2) the second order Fermi effect transfer energy from waves to cosmic ray, and (3) The work done by pressure gradient of cosmic ray and waves lead the plasma gain energy from cosmic ray and waves,vice versa.
In chapter 3, by using the MOCCT (Method of Characteristics/Constrained Transport) MHD code, we exploits a 3D numerical simulation, points on the Parker instability, but ingores the effects of self-gravity and waves. After sloved the diffusion term of cosmic ray energy equation via BICGStab (Biconjugate gradient stabilized) method, then obtained the convection trem and other MHD equations by modified Lax-Wendroff method. In general, we stduy 3D Parker instability including the cosmic ray effect with a hybrid numerical method.
During the epoach of non-linear stage, we found some characteristics: the cosmic ray pressure distribution is rather nonuniform. Cosmic rays tend to accumulate near the footpoint of the magnetic loop, and the cosmic ray pressure gradient force toward the top of the loop becomes larger. The falling motion of matter is then impeded by the cosmic ray pressure gradient force, and the growth rate of the Parker instability decreases. For 3D case, at near the end of evolution, due to the interchange mode participate in the system, the results are very different between 3D and 2D.
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