论文标题
磁性限制的等离子体的可用能量
Available energy of magnetically confined plasmas
论文作者
论文摘要
在磁性限制的背景下讨论了无碰撞等离子体的可用能量的概念。可用的能量量化了可以将多少等离子体能转化为波动（包括非线性的），因此是血浆稳定性的量度，可用于在不解决特征值问题的情况下得出线性和非线性稳定性标准。在磁性限制的血浆中，可用的能量由密度和温度曲线以及磁几何形状确定。这也取决于哪些约束限制了血浆运动的可能形式，例如保存绝热不变剂以及运输是双极性的要求。设计了一种基于Lagrange乘数的一般方法，以将这些约束纳入可用能量的计算中，并讨论了几种特殊情况。特别是，相对于频率超过离子弹跳频率的扰动，不可能将等离子体限制在麦克斯韦基态下的等离子体。
The concept of available energy of a collisionless plasma is discussed in the context of magnetic confinement. The available energy quantifies how much of the plasma energy can be converted into fluctuations (including nonlinear ones) and is thus a measure of plasma stability, which can be used to derive linear and nonlinear stability criteria without solving an eigenvalue problem. In a magnetically confined plasma, the available energy is determined by the density and temperature profiles as well as the magnetic geometry. It also depends on what constraints limit the possible forms of plasma motion, such as the conservation of adiabatic invariants and the requirement that the transport be ambipolar. A general method based on Lagrange multipliers is devised to incorporate such constraints in the calculation of the available energy, and several particular cases are discussed. In particular, it is shown that it is impossible to confine a plasma in a Maxwellian ground state relative to perturbations with frequencies exceeding the ion bounce frequency.
