Chirilă C C, Joachain C J, Kylstra N J, Potvliege R M
Department of Physics, University of Durham, Durham DH1 3LE, United Kingdom.
Phys Rev Lett. 2004 Dec 10;93(24):243603. doi: 10.1103/PhysRevLett.93.243603.
At high intensities, three-step recollision processes driven by low frequency laser pulses, such as high-order harmonic generation and high-order above-threshold ionization, are normally severely suppressed by the magnetic-field component of the laser field. It is shown that this suppression is not severe, even for ponderomotive energies well above 10 keV, for multicharged ions moving at a sufficiently high relativistic velocity against a counterpropagating infrared laser pulse. Numerical results are presented for high-order harmonic emission by a single Ne9+ ion moving with a Lorentz factor gamma=15 against a Nd:glass laser beam. The calculations are done within a Coulomb-corrected nondipole strong field approximation. The approximation is tested by comparing with accurate results.
在高强度下，由低频激光脉冲驱动的三步再碰撞过程，如高次谐波产生和高次阈上电离，通常会被激光场的磁场分量严重抑制。结果表明，对于以足够高的相对论速度反向传播的红外激光脉冲运动的多电荷离子，即使对于远高于10keV的有质动力能量，这种抑制也不严重。给出了单个Ne9+离子以洛伦兹因子γ = 15反向传播Nd:玻璃激光束时高次谐波发射的数值结果。计算是在库仑校正的非偶极强场近似下进行的。通过与精确结果比较对该近似进行了检验。
