Princeton Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543, USA.
Department of Astrophysical Sciences, Princeton University, Princeton, New Jersey 08540, USA.
Phys Rev Lett. 2015 Aug 14;115(7):075001. doi: 10.1103/PhysRevLett.115.075001. Epub 2015 Aug 11.
When the background density in a bounded plasma is modulated in time, discrete modes become coupled. Interestingly, for appropriately chosen modulations, the average plasmon energy might be made to grow in a ladderlike manner, achieving upconversion or downconversion of the plasmon energy. This reversible process is identified as a classical analog of the effect known as quantum ladder climbing, so that the efficiency and the rate of this process can be written immediately by analogy to a quantum particle in a box. In the limit of a densely spaced spectrum, ladder climbing transforms into continuous autoresonance; plasmons may then be manipulated by chirped background modulations much like electrons are autoresonantly manipulated by chirped fields. By formulating the wave dynamics within a universal Lagrangian framework, similar ladder climbing and autoresonance effects are predicted to be achievable with general linear waves in both plasma and other media.
当限制在等离子体中的背景密度随时间发生调制时，离散模式会发生耦合。有趣的是，对于适当选择的调制方式，平均等离子体能量可能会以阶梯式的方式增长，从而实现等离子体能量的上转换或下转换。这种可逆过程被确定为一种经典模拟，类似于称为量子阶梯爬升的效应，因此可以通过类比箱中量子粒子的方式直接写出该过程的效率和速率。在密集谱的极限下，阶梯爬升会转化为连续的自共振；然后可以通过啁啾背景调制来操纵等离子体，就像电子通过啁啾场进行自共振操纵一样。通过在通用拉格朗日框架内制定波动动力学，可以预测在等离子体和其他介质中的一般线性波中也可以实现类似的阶梯爬升和自共振效应。
