A variational principle for studying fast-wave mode conversion
A variational principle for studying fast-wave mode conversion
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研究快波模式转换的变分原理
DOI：
10.1088/0741-3335/40/11/010
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发表时间：
1998
期刊：
影响因子：
--
通讯作者：
R. Koch
中科院分区：
文献类型：
--
作者：
D. V. Eester;R. Koch
提出了一种研究托卡马克中离子-离子混合转换区附近一维波传播和阻尼的变分原理。在其变分形式中，波动方程与功率平衡方程密切相关：用电场代替其中的测试函数得出广义坡印廷定理。采用引导中心位置而不是粒子的位置作为自变量。环形和斜入射效应被保留，但极向磁场被忽略。麦克斯韦等离子体的严格正功率密度是通过从 Lamalle (Lamalle P U 1993 Phys. Lett. 175A 45; 1997 Plasma Phys. Control. Fusion 39 1409) 的一般形式开始并在每个引导中心轨道吸收功率的表达式中扩展作用于电场的算子（而不是像通常那样扩展介电张量）来确保的。 假设小参数 ，其中 是垂直波数和拉莫尔半径。提供了介电响应的一般公式，并给出了算子中保留高达二阶校正的情况的显式表达式。作为说明，讨论了辐射改进模式典型的 (H)-D-(Ar) TEXTOR 等离子体中射频功率的吸收。
A variational principle for studying one-dimensional wave propagation and damping near the ion-ion hybrid conversion region in a tokamak is presented. In its variational form, the wave equation is closely related to the power balance equation: substituting the electric field for the test function in it yields the generalized Poynting theorem. The guiding centre position rather than that of the particle is adopted as the independent variable. Toroidal and oblique incidence effects are retained but the poloidal magnetic field is neglected. A strictly positive power density for Maxwellian plasmas is ensured by starting from a general formalism due to Lamalle (Lamalle P U 1993 Phys. Lett. 175A 45; 1997 Plasma Phys. Control. Fusion 39 1409) and expanding the operator acting on the electric field in the expression for the absorbed power per guiding centre orbit (rather than expanding the dielectric tensor, as is usually done) in terms of the assumed small parameter , where is the perpendicular wavenumber and the Larmor radius. The general formulae for the dielectric response are provided and explicit expressions are given for the case where up to second-order corrections in are retained in the operator. As an illustration, the absorption of radio frequency power in a (H)-D-(Ar) TEXTOR plasma typical for the radiative improved mode is discussed.