Multi-wave and non-linear resonance heating in tokamak research Alfven eigenmodes

Title: Multi-wave and non-linear resonance heating in tokamak research Alfven eigenmodesAuthor: Yu LiminDegree-granting unit: Zhejiang UniversityKeywords: multi-scale expansion method;; Lie perturbation method;; radiation damping rate;; kinetic eigenmode negative shear QieaerfenSummary:Nonlinear interaction of waves and plasma in terms of controlled nuclear fusion plasma research, plasma physics or in the objects are very important issues. For example, in fusion plasmas, lower hybrid heating; in space plasmas, plasma waves to increase the role of the transverse kinetic energy; in the corona, the Alfven heating of ions and so on. For Rare earth magnets  more limited amplitude, low frequency electrostatic waves or Alfven heating or accelerating ions can cause problems is a very interesting and meaningful questions. As with the single large-amplitude high-frequency wave comparison, in the laboratory and space, is easier to achieve. Moreover, there is a general non-linear resonance condition Duo Bojia heat is a worthwhile consideration.As we all know, in care can mark (tokamak), the Alfven eigenmodes can be high-energy particle excitations. Excited Alfven in turn would undermine the constraints of high-energy particles. In addition, Alfven eigenmodes in the plasma is also very useful for the diagnosis, such as measuring safety factor. Therefore, the study of Alfven eigenmode existence and stability conditions is very important.In this paper, the use of multi-scale expansion method and Lie perturbation method focused on the multi-beam small-amplitude, low frequency electrostatic http://www.chinamagnets.biz/faq.php waves and nonlinear resonance Alfven speed, ion heating and the use of a non-disturbance of the (nonperturbative) Alfven eigenmodes numerical procedure is discussed in more detail in the tokamak plasma Alfven eigenmodes in the negative shear (reversed shear) under the kinetic effect, which specifically includes:The first chapter, an overview of plasma ion interaction causes the heating medium wave and the Alfven and the importance of tokamak.Chapter II, the use of single-particle model to study the multi-beam at different frequencies, and both the background magnetic field along the direction perpendicular to the propagation of electrostatic waves with ion interaction. Application of multi-scale expansion method, the amplitude of perturbation parameters for start, get a general analysis of nonlinear resonance conditions. By numerical calculation, to be in this condition, the ions can be multiple small amplitude, low frequency electrostatic waves efficiently accelerate or random heating, which verifies the theory. Compared with the single-wave heating in multi-wave case, the income threshold for random lower plasma is heated more easily. This is due to ions and multi-wave nonlinear effects occur, leading to a random island in phase space and random layer stacking spread more easily. This may be used as a coronal heating mechanism.Chapter III, multi-beam study of the different frequencies, and has a vertical shear 切阿尔芬波 Fang Xiangbo vector and ion interactions. Lie perturbation method applied to an amplitude of perturbation parameters for start, get a general analysis of nonlinear resonance conditions. By numerical calculation, verification of the nonlinear resonance conditions and get a random threshold. Compared with the single-wave heating, in the case of multi-wave random from a lower threshold, indicating that ions are heated more easily. This is due to ion and multi-wave nonlinear effects occur, leading to a random island in phase space and random layer stacking spread more easily.Chapter IV, including the development of a kinetic effect of non-disturbance MHD code to calculate the pressure effect, taking into account the tokamak plasma Alfven eigenmodes of the kinetic damping rate. This model to previous work [GY Fu et al., Phys. Plamsas 12,082505 (2005)] to promote them, to apply to general tokamak equilibrium, for example, contains a finite aspect ratio, finite magnetic pressure ratio and the non-circular cross section effects. Model cut 切阿尔芬波 kinetic effects from the hot ions, including hot-ion finite Larmor radius effects and the parallel electric field effects. Calculated by the program, to be in the negative shear plasma in the tokamak safety factor, negative cut Qieeerfen eigenmodes of the radiation damping rate (radiative damping) of the analytical form. Moreover, it reveals the existence of multiple kinetic eigenmode negative shear Qieeerfen and the discovery of the damping rate and the thermal ion Larmor radius and is linearly related to the number of shows with its radial wave damping rate increases. Found kinetic eigenmode negative shear Qieeerfen tokamak experiments can be used to explain the observed negative shear Qieaerfen eigenmode frequency becomes smaller over time phenomenon.Finally, concluding remarks and proposed job prospects.Degree Year: 2009