Troha A L, Van Meter J R, Landahl E C, Alvis R M, Unterberg Z A, Li K, Luhmann N C, Kerman A K, Hartemann F V
Institute for Laser Science and Applications, Lawrence Livermore National Laboratory, Livermore, California 94550, USA.
Phys Rev E Stat Phys Plasmas Fluids Relat Interdiscip Topics. 1999 Jul;60(1):926-34. doi: 10.1103/physreve.60.926.
The validity of the concept of laser-driven vacuum acceleration has been questioned, based on an extrapolation of the well-known Lawson-Woodward theorem, which stipulates that plane electromagnetic waves cannot accelerate charged particles in vacuum. To formally demonstrate that electrons can indeed be accelerated in vacuum by focusing or diffracting electromagnetic waves, the interaction between a point charge and coherent dipole radiation is studied in detail. The corresponding four-potential exactly satisfies both Maxwell's equations and the Lorentz gauge condition everywhere, and is analytically tractable. It is found that in the far-field region, where the field distribution closely approximates that of a plane wave, we recover the Lawson-Woodward result, while net acceleration is obtained in the near-field region. The scaling of the energy gain with wave-front curvature and wave amplitude is studied systematically.
基于著名的劳森 - 伍德沃德定理的外推，激光驱动真空加速概念的有效性受到了质疑，该定理规定平面电磁波不能在真空中加速带电粒子。为了正式证明电子确实可以通过聚焦或衍射电磁波在真空中被加速，详细研究了点电荷与相干偶极辐射之间的相互作用。相应的四维势在任何地方都精确满足麦克斯韦方程组和洛伦兹规范条件，并且在解析上易于处理。结果发现，在远场区域，场分布与平面波的场分布非常接近，我们得到了劳森 - 伍德沃德的结果，而在近场区域则获得了净加速度。系统地研究了能量增益随波前曲率和波幅的标度关系。
